Orchid Growing Training Course

Orchid Care Tips

The Internet's Original Orchid Growing Training Course. Discover the #1 most important step you should take to keep your orchid plants healthy, brilliant and insect-free. How do you know if your orchid plant it truly dead or just in a dormant state preparing to bloom again for you? Youll find out in our free course! A simple, easy method for knowing exactly when its time for repotting your orchids and giving them the best orchid propagation chances possible. Heres Just a Small Sampling of What Youll Discover in this Amazing Resource: Discover the common mistake everyone makes about epiphytic orchids and how to avoid it! Discover the 3 capacities of the labellum and why they are critical to your orchids survival. Learn the amazing prediction Darwin made about Xanthopan morgani praedicta. Here are 3 simple ways to insect-proof your greenhouse. When your orchid has exhausted its compost these 3 signs appear. Think all orchids offer nectar to insects? Find out why this common misconception is false and the Real trait all orchids share. These are the 7 crucial, life-giving minerals your orchid needs to survive. Learn why your pods might just contain over 186,300 seeds for propagation! Ever find your orchid blushing violently and then wilting? Put an end to it once you read page 4. Having problems feeding your epiphyte? This very special technique will solve your problems once and for all. Got Pests? Diseases? Spotted Flowers? This might be the silent killer youre facing. Learn the light trick and find out if your orchids Really have no more buds. How to tell the difference between monopodial and sympodial groups (and why the difference is important to your future as an orchid grower.) Read more here...

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Materia Medica of medicinally important orchids

Syn Arundina bambusifolia Lindl., Cymbidium bambusifolium Roxb. Common name Bamboo Orchid. Common name Hyacinthina orchid, urn orchid. Botany Bletilla striata is a deciduous terrestrial orchid. The tuberous rhizomes go up to 60 cm, papery, thin leaves. Light green leaves are plicate and are about 7.5 cm wide. Common name Lady's Slipper orchid. Distribution N. America to E. Asia - Japan. Common name Salampanja, Marsh orchis, salep orchid. Ayurvedic name Munjataka. Botany Dactylorhiza hatagirea is a terrestrial orchid with fleshy tuberous roots. Tubers are slightly flattened, palmately lobed. Stem is usually 30-50 cm tall, leafy and with few sheathing scales in the lower portion. Leaves are erect, oblong-lanceolate, 7-15 cm long, obtuse and with a sheathing base. Flowers are pink-purple, crowded in terminal, spicate racemes. Parts used Roots. Syn Habenaria arietina H.f. English name Wild orchid. Botany Orchis laxiflora is a terrestrial orchid with fleshy tuberous roots. Botany Vanda...

White Bog Orchid Bog Candles

White bog orchids grace the marshy meadows and wetlands. They are very similar to the greenish bog orchid (P. convallariaefo-but the flowers are snow white, and the plant is usually smaller and more delicate. It is also later blooming, and the fragrance is distinct, more perfumed than the greenish bog orchid. The Unangan gathered and steamed the roots of both these orchids for food.

Orchids and mycotrophy

Orchids deserve special note for the unique way they reap some of the advantages of large seeds without bearing the associated cost. Recall that juveniles succeed without reserves because germination and early growth are symbiotic. Establishment begins with invasion of the rudimentary endosperm-free embryo by a septate fungus, usually not a specific species (Fig. 5.2C Hadley 1982). Development takes place for a time, nurtured through fungal saprophytism or perhaps by attack on adjacent living bark tissue. Infection is contained intrusive hyphae are inhibited by phytoalexins and ultimately lysed to form pelotons that nearly fill hosting parenchyma cells (Fig. 4.15). Important physiological details remain obscure, but the orchid essentially acts as a necrotrophic parasite on what is normally a free-living or pathogenic fungus. Mycotrophic stages are briefer in epiphytic than in many terrestrial orchids greening and emergence of first leaves and roots are usually completed within a few...

Alaska Piperia Alaska Bog Orchid

Alaska piperia is easily distinguished from the other small orchids by its sweetish but disagreeable smell. Emerging from a tuberlike root, the single stem is slender, glabrous, grooved, and 6 to 10 tall. The two to three basal leaves are oblong to lanceolate, and 1 4 to 2 4 long. The upper stem bears two to three small and narrow leaf-like bracts. The bract below each flower is much shorter than the flower itself. The flowers are pale greenish and numerous, often more than twenty, and held in a tall narrow spike. Both the petals and sepals are greenish, and the spur is short and slender, about as long as the flower's lower lip. Alaska piperia is uncommon here and seems to prefer dry tundra, often near the beach. At first the scent seems sweet, but it soon hits you with an ammonialike pungency. The first collection of this orchid was made in Unalaska by Chamisso, the poet-naturalist and botanist sailing with Kotzebue in 1816-1817 aboard the ship Rurik. Emerging from a fleshy,...

Orchid Family Orchidaceae

Orchids emerge from bulbs, corms, rhizomes, or tuberous roots. Nearly all Aleutian orchids have very fragrant roots, even those with blossoms that have no fragrance. Many have a symbiotic relationship between their roots and certain fungi. For this reason, and the fact that many are rare species, it is best not to try transplanting them. The leaves of orchids are usually simple and entire, and they often sheathe the stem. The flowers are composed of three sepals and three petals, a deceptively simple theme which 26 the family has evolved into a diversity of exquisite flowers. The three sepals are usually alike and are often colored, resembling the petals or the bracts. Of the three petals, two are alike and held laterally like wings. The third and lower petal is usually markedly different, giving the flower its irregular ch shape. This lower petal forms a pouch in some species, as in the lady slip-O per (Cypripedium guttatum), or a lip which is often flared and sometimes includes a...

Purple Orchid Showy Orchid

Emerging from thick, forked tubers, the flowering stems are smooth and 5 to 8 tall. The leaves are lance shaped, up to 4 long, and often have dark purplish brown spots. The flowers are showy, held in a short spike and are rose purple, occasionally pink, or very rarely white. Purple orchids bloom very early in the spring, first appearing on south-facing hillsides and meadows. The earliest of them seem to flower on very short stems, because, unlike many other plants whose leaves appear first, the purple orchid's flowers push right out of the ground. Unlike the taller bog orchids, the flowers are not fragrant, and the plant is thought to be poisonous.

Bog Orchid Cornflower

Bog orchids bloom in the marshy meadows in early to mid summer. Distinguished from the white bog orchid (P. dilatata) by its greenish rather than snow-white flowers, the cornflower is also often more robust and blooms earlier. The two species are quite distinct on Unalaska Island, but there has been considerable discussion regarding names and hybridization of these orchids. The Unangan used the edible roots of both these orchids for food. They were said to be best steamed, and could be cooked covered with putchki (Heracleum lanatum) leaves.

Cranefly orchid

Orchidaceae (Orchid family) Ecology This relatively common orchid is easily missed because it's leafless in summer when the plant flowers and the slender flowering stalk and flowers blend in with leaf litter on the forest floor. In contrast, the dark green, 2-4 in. leaf (with a purple underside) stands out in winter against the mostly grayish brown forest floor. The only other wintergreen, summer-deciduous orchid in our eastern deciduous forests is putty root (Aplectrum hyemale). The flowers of cranefly orchid are pollinated by night-flying moths. As a moth inserts its head into the flower to obtain nectar, a pollinium (a tiny ball of pollen) is attached to the moth's eye and may inadvertently be deposited on the stigma of another flower. Amazingly, the deposition of pollinia on insect eyes is a common mode of pollen transfer in temperate orchids. Carbohydrates stored in the shallow-rooted corm are used to produce a new leaf in fall, and flowers, fruits, and seeds in summer. A lack of...

Choris Bog Orchid

Although reportedly quite common on Attu Island (Luer 1975), the tiny Choris orchid is on the Alaska rare plant list (Alaska Natural Heritage Program 2001). On Unalaska Island, it is not so much a rarity as simply difficult to find. This very small green-colored orchid blooms in late July, but is often nearly hidden in the damp mossy tundra and heath (Ericaceae). The plant was named for Louis Choris, the Russian artist who traveled in the Aleutians in the early 1800s.

Yellowfringed orchid

Orchidaceae (Orchid family) Ecology The flowers open sequentially from the bottom of the inflorescence to the top. The markedly fringed lower petal serves as both a visual attractant and landing platform for potential pollinators as they sip nectar from the long, down-turned spur. The primary pollinators are large butterflies, especially spice-bush swallowtails and palamedes swallowtails. The pollen of orchids is produced in discrete bundles called pollinia. As butterflies probe the nectar spur with their long tongues, the sticky end of the pollinium adheres to the eye of the butterfly. When the butterfly visits another flower, the pollinium may brush against the stigma, resulting in pollination. Without pollinators, no seeds are produced.

Bering Bog Orchid

The Bering bog orchid is regarded as one of North America's rarest orchids. While reportedly quite common on Attu Island (Luer 1975), it has only recently been recorded as far east as Unalaska Island (ALA Collection C. Parker, pers. comm.), where it is known from only one site. It was found blooming in late July in a wet and mossy meadow in Unalaska valley. As with the other species of Platanthera, the flower parts are very small, but the Bering bog orchid's long, thin and curving spur is easily noted. The yellow flowers, their lack of strong fragrance, and the plant's small size also distinguish it from the other bog orchids.

Nonorchid monocots

Bromeliaceae, with far fewer species and almost exclusively neotropical distribution, nevertheless rival Orchidaceae for variety of epiphytic mechanisms (Table 8.7) and vastly exceed the latter's biomass in tropical American forests. Tank habits have evolved independently in two brome-liad subfamilies, and in all three if sometimes-epiphytic Brocchinia (Fig. 4.25E) is correctly assigned to Pitcairnioideae (Benzing et al. 1985). A rosu-late shoot was required for each transference of absorptive role from root to foliage. Ancestry was apparently mesic in both Tillandsioideae and Pitcairnioideae (Fig. 2.4 Benzing and Renfrow 1971a Medina 1974 Benzing et al. 1985 - but see Pittendrigh 1948) tank shoots show C3 photosynthesis in each subfamily. Bromelioideae, with about 500 species capable of creating substitutes for ground soil in leaf bases, are fundamentally CAM plants that probably acquired nocturnal C02 fixation and impoundment as terrestrials in arid habitats. Specialization for PS...

Rattlesnake orchid

Orchidaceae (Orchid family) Taxonomy Orchids comprise the largest and most diverse family of flowering plants with over 800 genera and 25,000 species. Only 2 of the 100 species of Goodyera occur in the mountains and piedmont. The similar but less common lesser rattlesnake orchid (G. repens) has a basal rosette of dark green variegated leaves that lack a broad white stripe down the midrib. The infructescence (cluster of fruits) looks very much like the rattle at the tail end of a rattlesnake, and the unusual markings on the leaves resemble the skin of a rattlesnake, hence the common name. Ecology Rattlesnake orchid is one of our most common and easily recognized orchids. Individuals spread vegetatively by underground stems (rhizomes), so a single plant can have multiple rosettes, few of which bloom in any given year. After flowering, individual rosettes wither and die, but one or more new rosettes arise from a rhizome, ensuring survival. Enormous numbers of extremely tiny seeds are...


Orchidaceae owe their numerical superiority among epiphytes to an exceptionally propitious set of vegetative and reproductive features, including pollen conveyance by specialized insects lured by novel floral syndromes (Benzing and Atwood 1984). Vegetative mechanisms vary tremendously according to the taxon's native substratum and microclimate (Table 8.7), but there are several important attributes common to all canopy-adapted family members that, in some form, predisposed early stock for arboreal life. The specialized roots of epiphytic orchids vary in photosynthetic performance and water balance, depending on structure and metabolism uptake is enhanced in all cases by a nonliving velamen (Fig. 3.19) which imbibes precipitation containing solutes for subsequent sorption through transfer cells in an underlying exodermis. This same mantle effectively retards desiccation. Hyperovulate gynoecia and aggregated pollen characterize most of the family. Microspermy - up to millions of tiny,...


The plants belonging to the family Orchidaceae represent a pinnacle of evolutionary success in the plant kingdom. Represented by approximately twenty-five thousand species, they are possibly the largest family of flowering plants on Earth. Although orchids are most diverse in the tropics, they are found on every continent except Antarctica and can be found as far north as Alaska and as far south as Tierra del Fuego. Perhaps the main reason that orchids are so successful is that they have developed close relationships with insect pollinators and fungi. Their life histories are extremely complex and intricately woven together across three kingdoms of life Plantae, Animalia, and Fungi. Unlike other plants, orchid seeds contain no storage food for their dormant embryos. In order for most orchid seeds to germinate, they must be infected by fungal hyphae. After infection takes place, the orchid is able to take nourishment from the fungus, but it is unclear whether the fungus gets any...

Introduction Where do we go from here

Then, another age-old question - following upon the nuclear fusions, the zygote divides and embryogenesis is initiated what is it that activates the previously dormant egg Fertilisation also stimulates the primary endosperm nucleus into division, but none other in the sac or in the surrounding tissues is affected, indicating that the influences must be strictly localised. This question has exercised generations of cytologists, but the physiological problems involved have been largely neglected. Comparable events in animal fertilisation have been attributed to the release of second message after the contact of the sperm with the egg surface, and fertilisation in algae and fungi, more fully investigated than in the higher plants, provides other models. But the analogies may not be especially informative when it is not cells but nuclei that are involved in the first interactions. It is pertinent here that there are records from orchids with a simplified type of embryo sac of the egg...

Photosynthesis Of Cam Plants

In addition to plants that have the C3 and C4 photosynthetic systems, there is a third group of plants that keep their stomata open at night and fix CO2 into organic acids, especially malic acid (Salisbury and Ross 1978, p. 145). Their metabolism of CO2 is unusual, and because it was first investigated in members of the Crassulaceae (or orpine family), it is commonly called Crassulacean acid metabolism, often abbreviated CAM. CAM has been found in 18 families, including the Cactaceae (cactus family), Orchidaceae (orchid family), Bromeliaceae (pineapple family), Liliacea (lily family), and Euphorbiacea (spurge family). Many CAM plants are succulents, but not all. Some succulents, like the halophytes (plants that can grow in saline soils), do not possess CAM. Species with CAM usually lack a well-developed palisade layer of cells, and most of the leaf cells are spongy mesophyll. Bundle-sheath cells are present, but in contrast to those of C4 plants, they are similar to the mesophyll...

Unique Features of the Rain Forest Canopy

Indeed, the rain forest canopy may represent one of the most biodiverse biotas, perhaps containing between 50 and 80 percent of terrestrial species, depending on estimates. Besides the support trees, not only are many epiphytic plants (such as lianas, ferns, and orchids), arboreal mammals and reptiles, birds, and bats encountered, but unrivaled numbers of species of insects, spiders, mites, and other arthropods are also present. Ants represent the most regularly abundant animal group in the canopy, both in terms of numbers and biomass, whereas the most species-rich groups appear to be rove beetles (Staphylinidae) and weevils (Curculionidae). Typically, arthropod abundance and diversity are between two and four times higher in the canopy than in the understory.

Cotton Flower Cotton Grass Russett Cotton Grass

Blooming in marshes and wetlands, often among iris (Iris setosa) and bog orchids (Platanthera spp.), it sometimes covers vast patches, like summer snow fields. If picked before the seed loosens, cotton flowers can be hung upside down until the stems dry straight, and made into winter bouquets.

Production and Harvest

The first cutting of cork oak trees takes place when the trees are between fifteen and twenty-five years old, and produces virgin cork, which is of lesser quality than the cork that develops in the years following the initial cutting. While removing the bark cork layer, harvesters must avoid damaging the cambial layers beneath the accumulated outer tissues. The first cutting (virgin) cork is not discarded. Some virgin cork is used in the horticultural industry as a growing substrate for epiphytic plants, such as bromeliads, orchids, and certain ferns. The waterproof nature of the virgin cork, as well as its rough surface and resistance to decay, provides a long-lasting, natural medium onto which the epiphyte's roots may attach. The virgin cork is also ground up into small pieces, mixed with fillers, adhesives, and other materials to be manufactured into a variety of materials. Subsequent strippings of cork harvests are done at eight to ten year intervals. Each successive stripping...

Reproductive structures

Ripening capsules can constitute a large fraction of the reproducing orchid shoot. Thin wings with no obvious function beyond increasing photosynthetic capacity adorn some fruits (e.g., Encyclia cochleata Fig. 5.2H). Maturation is slow although final size is reached during the first few months, nearly a year is often required for dehiscence. In Encyclia tampen-sis, a green fruit wall more sparsely equipped with stomata (3-7 mm 2) than are the leaves (46 mm 2 on the abaxial surface) recaptures important amounts of C02 respired by developing seeds (Benzing and Pockman 1989). Several crop plants, despite less impetus to conserve water, also recycle C02 trapped in fruit locules, and may exhibit positive carbon balance. Reasons why green tissue in E. tampensis capsules, pseudobulbs, and roots mediate regenerative rather than net photosynthesis are discussed elsewhere (Benz-ing and Pockman 1989). Long-lived green flowers of certain moth-pollinated genera (e.g., Epidendrum) last for weeks if...

Contribution of the Stem

Some trees take on a candelabra appearance (e.g., buckthorn, lilac) because the apical meristem on the main axis dies at the end of the year and two or more branches grow out in its place. In the following year, the apical meristem of each branch dies and two new branches grow out in place of the old one. The death and replacement strategy creates plants with highly regular forms. The same strategy is found in Philodendron and Anthurium, common houseplants, and many orchids, although it is less obvious in these species because only a single replacement branch grows out and subsequent plant growth obscures the branching pattern. The horsechestnut (Aesculus) also has single replacement branches.

Habitats and Vegetation of Desiccation Tolerant Plants

The second DT plant dominated community can be found below 1,000 m, in very dry, exposed rocky places, e.g., in the Uluguru Mountains (Tanzania, East Africa), where there is a peculiar xerophytic vegetation, formed by the PDT model plant, the shrubby monocotyledon Xerophyta scabrida (Pocs 1976). This open bush dries up completely during the dry season, but turns into a vivid green during the rain. The species are highly adapted to very dry conditions. Below the shrubs, there is usually a dense mat formed by the poikilohydric Selaginella dregei, often accompanied by S. mittenii. In the herbaceous layer, poikilohydric ferns (Actinopteris dimorpha, Pel-laea schweinfurthii, and Piptadenia adiantoides), geophytes (Ophioglossum costatum, O. gomezianum, and O. lanczfolium), or therophytes are present (Borreria arvensis, Oldenlandia herbacea, and Heliotropium strigosum). The fibrous and persistent leaf sheaths of Xerophyta absorb some humidity even during the driest periods and provide...

Flower Volatiles as Mediators of Sex and Breeding Behavior in Insects

Representatives of all principal classes of floral scent chemicals have also been shown to be used by various insects, although not all these compounds are synthesized de novo by the insects (see the references in El-Sayed130). In insects, the compounds either mediate intraspecific interactions (i.e., they function as pheromones) or interspecific interactions (i.e., they function as allelochemicals). Some plants deceive insects to visit and pollinate their flowers by producing compounds that imitate pheromones or allelochemicals. The foul sulfur- or nitrogen-containing odors and thermogenesis in many species of Araceae imitate allelochemicals that elicit feeding or oviposition behavior in carrion and dung flies.36,48,131-135 Flowers of many deceptive orchid species produce compounds that mimic the sex pheromones of female insects (usually Hymenoptera) and elicit sexual behavior in males, which effects pollination through attempted copulation with the flowers (see Chapter 10).136-139...

Many Plants Are Endangered

One in ten, or a total of about three thousand plants native to the United States is endangered. Many of these endangered plants include some of the most showy, such as the large-flowered orchids. Increasingly, many plants around the world no longer reseed and therefore remain as lone survivors of their species. For example, the Presidio manzanita is so rare that only one plant survives in the wild, at San Francisco's Golden Gate Park. While cuttings have been propagated, they cannot self-fertilize. Another example of a lone survivor can be found on the Indian Ocean's Mascarene Islands where a palm tree, the Hyophorbe amaricaulis, survives as a single individual. One severe storm could cause its extinction. More than two hundred other plant species have also stopped reproducing. Worldwide, an impressive one in eight plants is endangered, according to the 1997IUCNRed List of Threatened Plants.

Carbon allocation and fluxes

It was believed from a very early stage that the fungal symbiont in mycorrhizal associations received its carbon nutrition from the host plant (Frank, 1885). Most of the ectomycorrhiza and ericoid mycorrhizal fungi have the potential to meet their carbon needs from external carbon sources when grown non-symbiotically in the laboratory. Nevertheless, it is generally agreed that they receive the majority of their carbon nutrition from the host plant while grown symbiotically. Since vesicular-arbuscular mycorrhiza have not yet been grown in pure culture it has been assumed that they receive their carbon nutrition solely from the host plant. In contrast, under natural conditions, the Orchidaceae are obligate symbionts with mycorrhizal fungi, and during the stage when orchids lack green leaves, the net movement of carbon compounds is from substrate through the fungus and into the host (Hadley and Purves, 1974 Purves and Hadley, 1975).

Commercial collection

More recently, commercial plant collecting on the southeastern Ivory Coast of Africa was responsible for reduced abundance of the epiphytic fern Platycerium stemaria, with note of the commercial value associated with nursery-grown or wild-collected epiphytic ferns across the globe (Porembski and Biedinger, 2001). Tree ferns are also important in the horticultural trade for landscaping, while their trunks are valued for orchid-growing medium and substrate. All species of the tree-fern family Cyatheaceae, all American species of Dicksonia (Dickso-niaceae), and Cibotium barometz (Cibotiaceae) (Zhang et al., 2002) are listed in Appendix II of the Convention of International Trade of Endangered Species (CITES) for trade monitoring. In 1997, export trade of C. barometz from China was prohibited due to the large quantities of individuals harvested and observations of reduced wild populations (Zhang et al., 2002). In Australia, Dicksonia antarctica was investigated for sustainable production...

Biochemical Aspects of the CAM Pathway

Given the expressive number of independent origins of CAM, great metabolic diversity can also be found among distinct CAM groups. Two major decarboxylase enzymes are responsible for releasing CO2 from malate during daytime PEP carboxykinase (PEPCK) and malic enzyme (NADP-ME and NAD-ME). Plants from the families Asclepiadaceae, Bromeliaceae, Euphorbiaceae, and Portulaca-ceae perform malate decarboxylation preferentially through PEPCK, while species from the families Aizoaceae, Cactaceae, Crassulaceae, and Orchidaceae have ME as the major decarboxylase. Thus, families with either type of enzymes occur within monocots and eudicots (Christopher and Holtum 1996).

Host Range and Growth Promotion Effect of Sebacinaceous Fungi

Members of Sebacinaceae were observed to be associated with a large number of mono- and dicotyledonous plants, inducing pronounced growth promotional effects (Table 2) Singh et al. 2001 Varma et al. 2001 , with the exception of the plants belonging to the Cruciferae and some plants belongingto the Chenopodiaceae and Amaranthaceae (Table3) Read 1999 Varma et al. 1999 Varma et al. 2001 Singh et al. 2003b . Literature suggests that the members of these groups normally do not form associations with AM fungi (Dension et al. 2003). Under in vitro conditions, P. indica Verma et al. and S. vermifera sensu Warcup and Talbot were demonstrated to interact with the root system of cruciferous and chenopodaceous plants, viz. mustard (Brassica junaceae), cabbage (Brassica oleracea var. capitata Kumari et al. 2003), Arabidopsis thaliana (Pham et al. 2004a) and spinach (Spinacia oleracea). A report indicated the ability of P. indica to colonize the rhizoids of a liverwort (bryophyte), and the thalli...

General Definitions and Apomixis Mechanisms

As apomictic reproduction entails the development of an embryo from a cell with a somatic chromosome number, several ways exist to produce embryos of apomictic origin. The simplest pathway avoids the production of a gametophyte, and a maternal embryo originates from one or more somatic cells of the ovule. This process is known as adventitious embryony, and can be either nucellar or integu-mental, depending on the tissue from which the embryogenetic somatic cell differentiates. Adventitious embryony seems to have evolved more frequently in tropical than in temperate flora. Moreover, it is more represented in diploid species, whereas other forms of apomixis are more frequent in polyploids. Among the agriculturally important species, adventitious embryony is found in several Citrus species, in mango (Mangifera indica) and in orchids. The most comprehensive treatise on adventitious embryony was published by Naumova (1992).

Distribution taxonomic and geographic

At the higher taxonomic levels, epiphytes are diverse excluding the mistletoes, 84 families, including 69 in Magnoliophyta, contain qualifying taxa. But rather few major clades account for most of the species just 23 families harbor about 98 of the total flora in 87 of the epiphytic genera (Tables 1.1, 1.2). Fifteen families include but a single epiphyte 52 of the 871 epiphytic genera contain five or fewer species, and about half of those contain only one. Heaviest contributors are Araceae, Bromeliaceae, Ericaceae, Ges-neriaceae, Melastomataceae, Piperaceae, Orchidaceae, Rubiaceae, and several fern families. Forty-three genera each contain more than 100 epiphytic species (Table 1.2) of the 43, 22 are orchids, 8 are ferns, 4 are bromeliads, 3 are from Aracaceae, and the remaining 6 are contributions from five additional families. Only 30 angiospermous genera containing epiphytes are found in more than one of the three major geographic regions just 13 of these inhabit tree crowns in...

Management of protected areas

In calcareous grasslands, cessation of management results in the development of a tall and dense herb and shrub canopy that eventually causes bryophyte diversity to decrease (van Tooren et al. 1991). In order to conserve the bryophyte species richness that is specific to the grassland vegetation, a certain amount of disturbance to prevent shrub recolonization is needed. Mowing is often implemented because of its positive effects for orchids. For bryophytes, however, mowing is not an optimal management strategy

Historical basis for canopy dwelling

There is now no way to explain fully why one lineage developed epiphytism while another did not. Partial answers are available in some cases, however several of the more notable ones are discussed below. Three questions provide focus Why are proportionally more ferns than seed plants epiphytic Why do so many monocots, particularly orchids, inhabit tree crowns Why have several families of dicots with no obvious advantage by basic habit or water balance mechanism succeeded so widely as epiphytes

Controversial Medicinal Plant Identification in Ayurevda

Proper identification of medicinal plants has a significant impact on the finished product and therapeutics. In Ayurveda identification of medicinal plants is a major hurdle in laying pharmacopeial standards for formulations. Astavarga (a group of eight medicinal plants see Table 5.24) is vital part of Ayurvedic formulations like Chyvanprasha and four plants viz, Riddhi, Vriddhi, Jivaka and Rishbhaka have been discussed as possible members of the family Orchidaceae. Although work has been done on identification of medicinal plants mentioned under Astavarga, much remains to be done to identify the true representatives. Table 7.1 Eight medicinal plants used in Ashtavarga. The plants marked with stars have been reported to be orchids. Table 7.1 Eight medicinal plants used in Ashtavarga. The plants marked with stars have been reported to be orchids. Orchidaceae Orchidaceae Orchidaceae Orchidaceae

Zheng 1996 In Medicinal Plants

Bechtel H, Cribb P, and Launert E. 1992. The Manual of Cultivated Orchid Species. 3rd Ed. Blandford Press, London. Bhandari SR, Kapadi AH, Mujumder PL. Joardar M and Shoolery JN. Nudol, a phenanthrene of the orchids Eulophia nuda, Eria carinata and Eria stricta. Phytochemistry. 24, 801-4. Fossen T, and Ovstedal DO. 2003. Anthocyanins from flowers of orchids Dracula chimaera and Dracula cordobae. Phytochemistry. 63, 783-7. Ghanaksh A, and Kaushik P. 1999. Antibacterial effect of Aerides multiflora Roxb. A study in vitro. Journal of Orchid Society of India. 13, 65-68. Khasin SM, and Mohana Rao PR. 1999. Medicinal Importance of Orchids. The Botanica. 49, Majumder PL and Banerjee S. 1987. Structure of moscatibn- a new derivative from Orchid Dendrobium moscatunm. Ind. J. Chem. Sec B, 26, 18. Majumder PL, Banerjee S, Maiti DC and Sen S. 1995. Stilbenoids from the orchids Agrostophyllum callosum and Coelogyneflaccida. Phytochemistry. 39, 649-653. Majumder PL, Banerjee S, and Sen, S. 1996....

Physiological and structural aspects of petal senescence

In the case of the longer-lived flowers, that is to say those usually persisting for several days or, in the case of certain orchids, several weeks, longevity is often modified by pollination and or fertilisation. A reduction in flower longevity, brought about by pollination, may have several benefits for a plant. Firstly, if sufficient pollen has been transferred to the stigma to bring about maximum seed set any further deposition of pollen is wasteful. Furthermore, the presence of excessive pollen tubes growing within the stylar tissues may result in competition for stylar food reserves. Thirdly, the maintenance of elaborate floral structures is a costly process, both in terms of respiratory substrate and the loss of water by transpiration. Lastly, the presence of large elaborate structures may make the plants more conspicuous and more liable to attack by herbivores (Dole, 1990). The senescence of floral tissues when they have completed their function must therefore be to the...

Microsporogenesis and Microgametogenesis

Pollen Development Stages

The tapetum plays an important role during several stages of pollen development. Its main function is the nourishment of the microspores but it also synthesizes enzymes (e.g., callase), exine precursors, pollen coatings, forms Ubisch bodies and viscin threads (both equivalents to the ektexine). The most striking material produced by the tapetum is pollenkitt (and tryphine in Brassicaceae, elastoviscin in Orchidaceae), a sticky, heterogeneous material composed of neutral lipids, flavonoids, carotenoids, proteins and polysaccharides. Pollenkitt serves numerous functions for example, keeping pollen grains together during transport protecting pollen from water loss, ultraviolet radiation, hydrolysis and exocellular enzymes maintaining sporophytic proteins inside exine cavities.

Influence of microhabitat

Because dispersal mode and seed size influence seed mobility and seedling establishment, they should be prominent factors in plant distribution within epiphyte communities. Two studies dealt with these phenomena and illustrate how additional parameters may alter expected patterns. Kelly (1985) found a marked correlation between vertical zoning and dispersal type in Jamaican wet montane forest. Nearly all the epiphytes anchored above 16 m (mostly orchids and tillandsioid bromeliads) bore small to minute wind-dispersed diaspores (Fig. 5.3). The incidence of species with fleshy fruit (mostly aroids) was greater in lower tiers, especially below 8 m. In all, 42.6 of the epiphytes had succulent fruit. Exposure and air turbulence were deemed critical for the observed segregation. Small seeds were considered the optimal type for upper-canopy life because there they can be wafted a long way by stronger wind currents. Moreover, intense irradiance reduces the need for extensive energy stores....

Retronecine Medicinal Uses

Of trachelanthamidine, e.g., of the phalaenopsine type, were known from different genera of the Orchidaceae (Hartmann and Witte 1995). A corresponding novel structural type of PAs named minalobines has been discovered in Ipomoea lobata (Cerv.) Thell. (syn. Mina lobata Cerv.), Spanish flag firecracker vine. This is a neotropical twiner with worldwide horticultural use as a popular ornamental due to its unusual corolla form, stamens and style finally twice as long as the corolla, and unusual colours (red, later becoming whitish or pale yellow). Altogether 21 minalobines (congeners A-U) could be identified, 19 from I. lobata and additional two from I. cristulata (Jenett-Siems et al. 2005a). They turned out to be esters of (-)-trachelanthamidine (Fig. 3.29) with just the same necic acids already known from the ipangulines. Due to the lack of a hydroxyl group at C-7 only an esterification at 9-O is enabled. Furthermore, in contrast to (-)-platyne-cine the hydroxymethyl substituent at C-1...

What Are The Medicinal Uses Of Tillandsia Usneoides Medicinal

Most Important Positions Boat

Local bromeliads and epiphytic orchids (Table 6.11). Conversely, Ficus aurea failed to nurture even one of the hundreds of seeds glued to its smooth, stable bark over the four-year survey, perhaps for the same reason that extracts of this tree inhibited germination of the orchid Encyclia tam-pensis in another study (Frei and Dodson 1972). Bursera simaruba, at best an occasional substrate for Florida Bromeliaceae, and then only in cracks and knotholes, regularly shed bark in small fragments, often with test subjects attached (Fig. 7.7F). Both Bursera and Ficus retain considerable foliage most winters in Florida, rendering their crowns darker and therefore even less suitable for heliophilic Tillandsiapaucifolia than those of fully deciduous cypress. Controls affixed to cedar lathe and maintained under a daily greenhouse mist regimen germinated at 90 during each of the four years.

Circumscribing labeling and documenting the epiphyte community

Segregation (in terms of water-carbon balance mechanisms) of canopy-adapted floras into vertical strata has already been described (e.g., Pitten-drigh 1948 Benzing and Renfrow 1971c Griffiths and Smith 1983). Johansson (1975) was able to identify five life zones in some West African trees, three at different depths in the crown plus one on the upper and one on the lower trunk (Fig. 7.10). Each had its unique set of orchid occupants, albeit with a certain amount of overlap Percentages of the total orchid flora at each location varied from 4 at the crown periphery to 48.5 at midcrown, where shade was moderately deep and moisture more abundant. Percentages for the crown center and upper and lower trunk zones were 27.7, 10.9, and 8.9, respectively. Presumably, survival on outermost twigs was tested most by drought, whereas light was probably the limiting resource deeper in the canopy. Gentry and Dodson (1987b Fig. 2.20) and Catling, Brownell, and Lefkovitch (1986) noted similar epiphyte...

Plastids In Root Of Taeniophyllum

Velamen Radicans

Photosynthetic roots deserve special mention in this discussion because they are featured by so many epiphytic orchids and aroids. Plastids responsible for the green color in an orchid root reside in cortical (Fig. 2.16) and less often stelar (Fig. 2.14) parenchyma, including the endodermis. Chloroplasts are scattered and relatively few per cell, much as they are in a CAM plant's succulent leaf and stem. If exposed on all sides, roots are uniformly pigmented. Those growing against solid objects remain achlorophyl-lous or pale green where contact blocks light. Embedded roots, of course, are incapable of autotrophy. Most orchid roots are oval to round, but those of shootless Campylocentrum pachyrrhizum and several Phalaenopsis have become almost planar. Taeniophyllum rhizophyllum roots are, as the name implies, even more leaflike. Structural features that might logically reflect trophic capacity do in fact seem to be related to photosynthetic vigor. One of these is root mantle...

Tillandsia Usneoides Eesential Oil Yield

Tillandsia Usneoides

Even though fossils and the geographic distributions of surviving lineages indicate phylogenetic youth, Bromeliaceae exceed many of the pre-Tertiary clades (e.g., Fagaceae, Platanaceae, Juglandaceae) for number of species and especially for adaptive variety (e.g., diverse habits, habitats). Capacity to produce a simple, cheaply constructed, rapid-cycling body varies among the magnoliophytes, and helps explain why some families (e.g., Asteraceae, Poaceae, Orchidaceae) contribute more extensively to angiosperm diversity than predominantly woody groups. Additional plant characteristics, such as the tight relationships between numerous orchids and their high-fidelity pollinators and propensity to exploit underutilized ecospace (e.g., forest canopy), in turn account in part for the different sizes of the largely herbaceous clades. Although relatively modest by membership, perhaps because of weaker propensity for speciation, Bromeliaceae exceeds these largest taxa for certain other kinds of...

The epiphytic habitat

Philodendron Epiphyte

Most forest dominants are trees which grow up from the ground without passing through an epiphytic phase, but some start out as primary strangling hemiepiphytes. A number of true and facultative epiphytes are shrubs, a few growing several meters tall (e.g., Blakea, Rhododendron). All but the most specialized mistletoes are shrubby. Occasional woody forms (e.g., Ficus as juveniles, Markea, some Ericaceae) and pseudobulbous orchids (Figs. 1.10, 1.15) produce storage tubers. Swollen hypocotyls of suffrutescent Myrme-codia and Hydnophytum (Fig. 1.4) also house ants that provide mineral ions (Huxley 1978). Thickened rhizomes of some ferns (Fig. 4.24E-G) perform much the same way. Broadly creeping taxa with herbaceous or woody stems are well represented in Asclepiadaceae (Fig. 4.24C,D), Ericaceae, Gesneri-aceae (Fig. 1.17), and several fern families (Fig. 1.6). Rosulate shoots are best developed in Bromeliaceae (Fig. 1.2) in Anthurium (Fig. 1.5) and (fewer) Philodendron in Liliaceae...

Structural adaptations to drought

Loa Voodoo

Vascular plants maintain serviceable water economy by utilizing a variety of coordinated structural and dynamic measures. The uncommon poikilohydrous epiphyte with its lightly insulated foliage loses water quickly desiccation is not fatal, however. The less tolerant homoiohydrous species must deploy special anatomical features (Fig. 3.1) as a first line of defense against lethal drying xerophytes possess stout-walled epidermal cells covered by a thick evaporation-retarding cuticle. Mesophyll is commonly differentiated into hypodermis and chlorenchyma. A largely achlo-rophyllous, multilayered, adaxial epidermis occupies up to 80 of total leaf volume in some epiphytic Peperomia (Kaul 1977). Much of the leaf interior assumes a similar water-storage role in numerous dry-growing Bromeli-aceae, Gesneriaceae, and Orchidaceae. Succulence and CAM usually coincide, but some epiphytes are exceptions. A sizable hypod6rmis is indeed a poor indicator of CAM in Orchidaceae, just as Guralnick et al....

Reproduction and life history

If breeding systems differentiate terrestrial from canopy-based pte-ridophytes, the fact remains unreported. Comparisons of angiosperms are easier, and pollination has been studied in numerous epiphytic flowering plants, especially neotropical Orchidaceae. Pollinators of these taxa tend to be more species-constant and specialized than those serving nearby terrestrials, although sharing of pollinators is sometimes possible. Avians are especially important in northern South America, where nectar-feeding birds and the flora they serve reach unparalleled diversity. Large, heavily ornithophi-lous families include Bromeliaceae, Ericaceae, Gesneriacese, and Lorantha-ceae birds frequently pollinate Cactaceae, Marcgraviaceae (Norantea), and Rubiaceae (Ravnia, Manettia) as well. The relationship between epiphytism and avian pollination is particularly apparent in families with diverse floral syndromes. Ornithophily in Bignoniaceae is rare except in two epiphytic genera Gibsoniothamnus is...

Ground soil conditions

Probably also arose at different locations in some wide-ranging genera (e.g., Begonia, Gaultheria, Pilea, Solanum, Utricularia). In others (e.g., Clusia, Coprosma, Ficus, Griselinia, Luzuriaga, and Peperomia), long-range dispersal occurred almost certainly after founders were able to grow in tree crowns. Except for the ferns, strangler figs, Peperomia, Rhipsalis, and a few orchid genera, the epiphyte floras of different continents were seemingly derived independently (Gentry and Dodson 1987b). Most diverse on taxonomic grounds are the epiphytes that colonize suspended soils in humid forests. Virtually every family containing epiphytes includes at least one such humiphile most contain no other type. Where aridity is pronounced, few higher taxa are represented, although these are sometimes species-rich (Benzing 1978a). Neotropical ant nest-gardens provide substrata for a modest myrmecochorous flora which often offers food to ants. Perhaps additional traits as yet unrecognized that might...

Phylogenetic Distribution of SI Systems

Fig. 4.1 Phylogenetic distribution of SI and self-sterility (SS) systems within the angiosperms Phylogenetic relationships between taxa are based on the current angiosperm phylogeny (APG II, 2003). The presence of SI SS was mapped using MacClade 4.0. There is evidence for the presence of SI SS in the following families Nymphaeaceae (equivocal, see Sect. 3.2.1), Austrobaileyaceae, Illiciaceae, Trimeniaceae, Chloranthaceae, Winteraceae, Saururaceae, Lauraceae, Magnoliaceae, Annoneaceae, Magnoliaceae Degeneriaceae, Orchidaceae, Amaryllidaceae, Hemerocallidaceae, Iridaceae, Asphodelaceae, Liliaceae, Melanthiaceae, Poaceae, Bromeliaceae, Commelinaceae Pontederiaceae, Ranunculaceae, Papaveraceae, Nelumbonaceae, Chenopodiaceae, Caryophyl-laceae, Polygonaceae, Plumbaginaceae, Olacaceae, Santalaceae, Saxifragaceae, Grossulariaceae, Myrtaceae, Onagraceae, Lythraceae, Passifloraceae Linaceae, Clusiaceae, Erythroxylaceae, Turn-eraceae, Oxalidaceae, Connaraceae, Fabaceae, Fagaceae, Nothofagaceae,...

Atmospheric nutrition

Polyradicion Species

Neither humus nor appreciable animal products are available to PS species. At the extreme, mist and root leaf tangle epiphytes of Orchidaceae barely contact host surfaces at all (Fig. 1.7). Certain atmospheric bromeliads possess roots that securely grip the substratum but are essentially nonab-sorptive (Fig. 1.11). Those of some other forms (e.g., certain ferns, Hoya) often seem too reduced to provide much benefit beyond mechanical support. As noted previously, the specialized shoot epidermis and root mantle alternatively promote hydration and reduce drought stress for many bromeliads and orchids. Similar or analogous features may exist in other taxa. The velamen of orchids, which proves so efficacious for water balance, may have another impact on mineral nutrition, especially where nutritive fluids arrive sporadically. It is not clear at this point how different thicknesses and arrangements of rhizodermal cells (Fig. 3.19A-G) affect bulk exchange between imbibed canopy fluids and...

Inputs from fungi and diazotrophs

Figures 4.3-4.9. (4.3) Microbiology of the epiphyte rhizosphere (4.3) multicellular rounded spores associated with root of Macleania cordifolia (Ericaceae) (4.4) hyphae and vesicles on surface of root of Clusia sp. (Clusiaceae) (4.5) hyphae and fungal inclusions in root of Topobea sp. (Melastomataceae) (4.6) cyanobacterium on surface of root of Peperomia cacaophylla that had been growing in an ant nest-garden (4.7) chlamydospores produced by a fungus associated with Topobea sp. (4.8) network of thin, poorly staining hyphae and elongate multicelled spores associated with root of Macleania cordifolia (4.9) fungal coils in a root of the orchid Campylocentrum fasciola. Bars 100m- Figures 4.10-4.15. (4.10) Fungal hyphae infecting root cortical cells of the shootless orcnia Polyradicion lindenii. (4.11) The upright habit and loose cuticular wax on leaf bases of Catopsis berteroniana. (4.12) Fungal hyphae infecting a passage cell between thicker-walled U cells in the root exodermis of the...

Influences of pollinators

Some bromeliads follow more episodic schedules characterized by orif-erous days interspersed among barren ones (e.g., T. schiedeana, Vriesea splendens). Fragrant, night-blooming Tillandsia dodsonii exhibits an especially curious pattern better known in some Neotropical orchids. Thousands of plants simultaneously, but irregularly, each produce one to four fragrant, nocturnal owers with large, white to creamy corollas per distichous, pendant spike (Fig. 3.5F). Cool nights following late afternoon showers supposedly promote this kind of behavior in Sobralia in some of the same Ecuadorian habitats. However, stimuli with the same effect operate elsewhere. Three colonies of T. dodsonii maintained under glass at the Marie Selby Botanical Gardens in Sarasota displayed 12 owers on eight spikes on 18 December 1996 (Benzing, personal observation). Nothing followed until ve nights later when 12 more buds opened on the same in orescences.

Leaf variegation and shoot architecture

Figures 2.8-2.13. (2.8) Peperomia tropaeolifolia growing at the base of a tree in rain forest at Rio Palenque, Ecuador (X ). (2.9) Vriesea erythrodactylon (X)i) note deeply cyanic leaf bases. (2.10) Eroding veiamen of the shootless orchid Campylocentrum pachyrrhizum. (2.11) Tillandsia utriculata growing in deep shade in a South Florida swamp forest (XXo). (2.12) Tillandsia utriculata growing in nearly full sun in South Florida (XKo). (2.13) The central part of a tank shoot of Vriesea fosteriana (X ). Wallace (1981) noted vertical distribution of vascular epiphytes relative to carbon fixation pathway in a humid Australian forest (Table 7.2). Ten ferns and 14 mostly orchidaceous angiosperms were surveyed. Species in shady locations on lower trunks and along large branches were all C3 ferns and woody hemiepiphytes. Those at the upper canopy margin were predominantly CAM species, as determined by 5'3C assays. Among the few highly exposed C3 types were a woody epiphyte (Pittosporum...

Economic and Ecologic Importance

Many of the most important plant species grown for human consumption are in the grass family, which includes rice, corn (maize), wheat, rye, barley, teff, millet, and other species. Many species of the grass family are also grown for animal consumption or as lawn grasses examples include timothy, fescue, and bluegrass. Another group of great economic importance is the palm family, which includes coconuts, dates, and the oil palm. In addition to these foods, the palm family provides construction materials for housing, thatching, and a variety of tools and implements in many parts of the world. The largest family of monocots, in terms of number of species, is the orchid family. Although orchids are widely grown as ornamentals, only one species, the vanilla orchid, is grown as a food plant. The flavoring agent vanilla is extracted from the podlike fruits of this species. Apart from their obvious economic importance as sources of foods and other materials of use to humanity, various...

Decrease in Biodiversity

In the German flora, orchids are particularly protected, but despite this the distribution of all orchid species has significantly decreased (Fig, 5.5.2B). Species covering less than 100 grid cells (2x2 km) at the beginning of the last century are now almost extinct (2000 a.d.), showing the limitations of methods of protection, and also how relatively rare species assume a particular and important indicator function, to illustrate the effects of global change. ig. 5.5.2. A Anthropogenic factors that led to extinction of species in Germany (from Schulze and Gerstberger 1993). B Distribution of species of orchids in Thuringia, Germany, before 1990 (observed since 1900) compared to the period after 1990. All species showed a decline in distribution in about 150 grid cells (2x2 km). Each dot represents a species of orchid

Phytochemical Investigation On Lyonia Ovalifolia And Related Medicinal Plants

The flora of the Himalayas varies with climate, rainfall, altitude, and soils and includes elements from tropical Indochina, temperate East Asia, the Palaearctic region, the Deccan Plateau and the low-lying areas along with the support of mixed evergreen forests. Although most of these semi-evergreen forests have long since been converted into human uses, vestigial patches appear mostly in small protected areas. The alluvial grasslands and savannas along the foothill valleys are among the tallest in the world. Characteristic species in these highly productive grasslands include Saccharum spontaneum, Phragmitis kharka, Arundo donax, Imperata cylin-drica, Erianthus ravennae, Andropogon spp., and Aristida ascensionis. The lower hill slopes above 1,000 m are cooler and less drought-stressed. These areas are dominated by subtropical evergreen broadleaf forests. The eastern Himalayas' temperate forests are dominated by evergreen broadleaf trees and mixed conifers (e.g., Quercus, Lauraceae,...

Erwinia chrysanthemi A Pathogen Of Agricultural Importance

Pectinolytic Erwinia, recently reclassified in the genus Pectobacterium, forms one of the two groups within enterobacteria that contain species pathogenic to plants. A typical member in this group is E. chrysanthemi, a pathogen that can prosper in various environments and cause disease in economically important plants, including vegetables (potato, chicory, maize, etc.) and ornamentals (African violet, carnation, orchids, etc.). Soft rot, the most visible symptom induced by this species, results from the degradation of pectin, the major component of primary cell walls. E. chrysanthemi attacks storage organs and fleshy plant tissue, particularly when physiologically compromised by bruising, excess of water or high temperature. This bacterium is also associated with systemic and latent infections in growing plants of many species. It is generally not endemic in soil (Perombelon and Kelman, 1980). It can overwinter in contaminated plant residues, remaining in the soil after harvest....

Dispersal and establishment pattern

Madison's (1979b) study in North Borneo provides interesting commentary on wind versus animal dissemination in a heterogeneous group of 25 epiphytes. Although his survey was static in the sense that history was inferred from a single census, characteristics of the site eliminated much complicating postdispersal influence on plant distribution. Subjects were arrayed through an even-aged rubber tree plantation so that spacing, tree size, and type were relatively uniform (Fig. 5.5). Initial recruitment occurred from nearby older plantations, and also (though probably to a lesser degree) from native forest no farther away than 0.5 km. Anemochores were produced by nine orchids, six ferns, and six asclepiads ornithochorous species were two Rubiaceae, one mistletoe, and a melastome. The rubber trees had been growing long enough to allow some, if not all, sampled epiphytes to reproduce within plantation boundaries. Figure 5.5 shows that each of the fern and orchid species examined by Madison...

Factors Threatening Species

Overharvesting of plants, often for food, medicinal purposes, or by horticulturists, threatens 10 percent of the endangered plant species of the United States. A notable example is ginseng, an herb used in Asian medicine, which has been so overharvested throughout its range that only a small number of plants remain. Many rare wildflowers, such as orchids, have been so severely overcollected by gardeners that they are in danger of extinction in the wild. Information on the location of the last remaining plants is often kept secret to prevent the theft of these individuals.

Mutually Beneficial Coevolution

The evolution of mutualism provides opportunities for deception. For example, many species of orchids produce colorful flowers and odors but provide no reward. They depend on mistakes made by inexperienced bees to get their pollen onto a vector. To ensure that a mistake pays off, the orchid is constructed so that any visiting bee necessarily carries away the pollen in sticky packets called pollinia deposited on its body. The flower is constructed so that when the bee makes a second mistake the pollinium is removed and deposited on the stigma of the second flower. Pollen transfer has to be efficient terrestrial orchids in temperate North America may only be visited once in a decade. Some tropical orchids improve their chances of being visited by producing volatile chemicals that are collected by certain bees and used as mating signals. Some orchids may produce an odor that mimics a bee's mating signal, attracting bees that are then disappointed in finding no mate, but carry away a...

Regulation Of Scent Biosynthetic Pathways

Of the plant organs in scented species, flowers produce the most diverse and the greatest amount of volatile compounds, which peak when the flowers are ready for pollination. Within the flowers, the petals are the principal emitters of volatiles, although various other parts of the flower may also participate in fragrance emis-sion.73-74 While the same floral scent components are often emitted from all parts of the flower (although not necessarily at the same amount or rate), sometimes specific compounds may be emitted from only a subset of the floral organs.75-79 In addition, as discussed in Chapter 6, in some species (e.g., orchids), floral volatiles are emitted from highly specialized scent glands (i.e., osmophores) within the flower. S0-S1 It is not yet clear how prevalent scent glands are among other scented flowers. So far, investigations of scent glands have been conducted mostly on the anatomic level. The question of whether such glands represent sites of emission only, or...

Self Incompatibility in the Monocots

The best-studied SI system in the monocots is the two-locus GSI system of the grasses (Poaceae) (discussed in detail in Chap. 13), but other well-studied taxa include Narcissus (Sage et al. 1999), Trillium (Sage et al. 2001), Tradescantia (Owens and McGrath 1984), Lilium (Lundqvist 1991 Tezuka et al. 2007), Gasteria (Naarborg and Willemse 1992) and Eichhornia azurea (Bianchi et al. 2000), and reflect the spectrum of different SI self-sterility systems present in this major group. Members of the largest angiosperm family, the Orchidaceae, employ a vast range of mechanisms to promote outbreeding, including many examples of SI (presumed to be GSI) and self-sterility (Borba et al. 2001). However, despite predictions of the presence of such mechanisms in over 750 species (East 1940), little is known about the physiology and genetic control of SI in the Orchidaceae on account of their very long lifecycles, which effectively preclude genetic analysis.

Climate elevation and latitude

Epiphytes occur along a broad moisture continuum ranging from pluvial woodlands to cactus savannas and microphyllous forests. Biomass, diversity (Fig. 1.21), and habit all vary along this axis, with each parameter usually increasing as seasonality and hence aridity diminish. Wallace (1981) recorded decreasing numbers of epiphytic species across increasingly dry forests (Tables 8.3, 8.4) in eastern Australia. Sanford (1974) documented a similar sequence in his survey of epiphytic orchids along a rainfall gradient in Nigeria. Length of dry season (about one to four months) and WVPD were more important determinants of floristic richness than was total rainfall. A second set of three Australian sites chosen by Wallace to illustrate low-temperature effects, including occasional frost at the extreme, yielded 28, 20, and 13 epiphytic species. Gentry and Dodson (1987b) thoroughly demonstrated the effects of climate on epiphyte success (Figs. 8.3, 8.4). Flo-rulas were developed at three sites...

Halophytes Versus Glycophytes

Many groups of plants are considered as sensitive (e.g. conifers, ferns, Orchidaceae, Araceae, Rosaceae, Ericaceae and molds), while particular families comprise tolerant genera and species, such as Potamogetonaceae, Plumbaginaceae, Zygophyllaceae, Frankeniaceae, Tamaricaceae, Rhizophoraceae, etc. (Waisel, 1972). It is interesting that the widespread Chenopods may be designated as halophytes per excellence (Flowers and Yeo, 1988), as half of the total genera successfully grows in conditions of salinity (Atriplex, Suaeda, Salsola, Camphorosma, Salicornia, etc.).

Modified Roots and Their Economic Importance

In warm climates where freezing is not a problem, roots can grow above ground where they assume diverse functions. Above-ground roots are well developed in orchids, fig trees, and mangroves growing throughout the tropics and subtropics. The orchid family includes climbing orchids and epiphytes that live on tree branches, close to sunlight but away from soil. Roots of the vanilla orchid emerge from the stem and support this climbing vine by twining around sticks and branches of trees. Roots of epiphytic orchids are out in the open where they have access to sunlight and rainwater, but not to soil. Long-term studies at Hummingbird Cay Tropical Field Station in the Bahamas show these orchids grow very slowly but live for decades. Their aerial roots have a spongy multilayered epidermis called velamen that enables roots to store water from rain and bark runoff. To the inside of the velamen the cortex is modified for photosynthesis, performing a function usually restricted to leaves....

Biodiversity and Ecosystem Processes

Versity, then it is not sufficient to just compare sites with different diversity (e.g. an orchid-rich hornbeam forest and a species-poor spruce forest). The biogeochemical cycles in natural or managed ecosystems (Chap. are influenced by many uncontrollable factors, such as history, which makes specific experimental investigations necessary.

Interactions Plant Plant

Commensalism occurs as one species lives in a direct association with another (the host), gaining shelter or some other environment requisite for survival and not causing harm or benefit to the host. Orchids and bromeli-ads (Neoregelia spp.) live on the trunk or branches of their host, gaining water and nutrients from the air or bark surface without penetrating host tissue. Stocky roots and xeromorphic leaves that help gain and retain water are characteristic of vascular epiphytes (epiphyte means to live upon another). Bryophyte, lichen, and fern epiphytes are so abundant in the tropical rain forest that they often embody more plant material than their host trees. Another facilitation is illustrated by seedling growth of the Saguaro cactus (Cereus giganteus), which typically occurs in the shade of paloverde trees or

Habitat fragmentation degradation and destruction

Similarly, tree plantations in New Zealand disrupt forest structure and diversity (Ogden et al., 1997). However, increased plantation stand age was related to increased species richness and forest composition of woody shrubs, tree ferns, and terrestrial understory ferns, with tree ferns reaching higher densities and species richness in older stands (Ogden et al., 1997). Forest recovery after agricultural use also has long-term effects on forest structure Dominican Republic forest life-form diversity declined in a 40-year-old secondary forest compared with old-growth forest, with old-growth forest containing fewer introduced species and more arborescent ferns, palms, epiphytic bromeliads, orchids, bryophytes, terrestrial understory ferns, and other herbaceous plants (Martin et al., 2004). These structurally diverse plant communities provide important habitat for ferns and lycophytes and are often biodiversity hot-spots. The temporal scale of postagriculture forest recovery depends on...

Adjustment of conductance

A few studies have examined the role of stomata as humidity sensors in such epiphytes as the deciduous C3 orchid Catasetum integerrimum and some bromeliads, including the CAM xerophytes Tillandsia usneoides and T. recurvata. Carbon dioxide consumption by the Catasetum plummeted under steady high-level PAR immediately after RH was abruptly depressed from about 70 to 40 (Benzing et al. 1982a). When RH again approached 100 in the sample cuvette, the orchid's gas exchange returned to pretreat-ment rates within an hour or two. Tillandsia recurvata (Lange and Medina 1979) responded to drier night air in much the same fashion as did T. usneoides (Martin and Siedow 1981 Fig. 3.2). Griffiths et al. (1986) noted

Mycorrhiza and its role in the environment

Its characteristic feature is the possibility to penetrate not only spaces between cells, but also the inside of live cortical cells, crossing the cell wall and then developing in touch with the plasma membrane of the plant cell. This type of symbiosis includes orchid, ericoid, and arbuscular mycorrhiza. In the first two types, the mycelium forms coils inside cortical cells, but in arbuscular mycorrhiza, characteristic tree-like structures termed arbuscules develop. Arbuscular mycorrhiza (AM) is the most widespread type of mycorrhiza, occurring in 80 of plant species it is formed by about 120 species of fungi belonging to the Glomeromycota 10 . This symbiosis is believed to be phylogenetically the most ancient type of mycorrhiza.

Why are bryophytes threatened

The high water-holding capacity of bryophytes, especially those with highly specialized hyalocysts such as Leucobryum and Sphagnum, makes them a useful potting medium, particularly favoured by orchid growers and for wrapping flowers or fruit tree rootstocks for transportation (Box 2.1). At present, although outdoor Sphagnum nurseries are an interesting option for a new type of professional horticulture (Rochefort & Lode 2006), bryo-phytes are directly harvested from natural populations. Local regulations sometimes exist (for example, the EU Directive 92 43 EEC (Habitats Directive) in Europe, DC0162(02) EN HTML and the Flora and Fauna Guarantee in Victoria, Australia), but this activity is not monitored globally and can result in considerable ecological damage and decline in bryophyte diversity. Initially mostly focused on Sphagnum (e.g. Whinam & Buxton 1997), commercial moss harvest has been increasing and expanding to other taxa, including epiphytes. Epiphytic moss harvest is most...

Avenues for Mitigating the Cost of Reproduction

Some of the resources invested in reproduction are recoverable and this may partially mitigate proximate costs. Any structure that remains attached to the parent plant, rather than being abscised or dispersed at maturity, contains potentially reclaimable nutrients. For example, reabsorption of unremoved nectar occurs in some plant species (e.g., Burquez and Corbet, 1991), and there is evidence that reabsorption of these energy-rich sugars increases fruit quality and seed fitness in an epiphytic orchid (Luyt and Johnson, 2002). A study in Sidalcea oregana revealed that in contrast to plant parts shed at maturity (pollen and seeds), 50-80 of nitrogen and phosphorus is reabsorbed from floral structures that remain attached to the plant (calyces, petals, unfertilized ovules Ashman, 1994b). There is also potential for the reabsorption of resources from early aborted fruits, although there is little evidence to address it (Obeso, 2002). In contrast to unfertilized ovules, plants are not...

How Diverse Are Floral Scents

So far, more than 1700 compounds have been identified in the floral headspace of 990 taxa (most at the species level) belonging to 90 families and 38 orders.18 The majority of these taxa (78 ) belong to the following 19 plant families, in each of which floral scent composition has been characterized from at least 10 or more taxa listed in descending order of taxa (taxa number given in parentheses) Orchidaceae (417), Araceae (55), Arecaceae (40), Magnoliaceae (26), Rosaceae (24), Cactaceae (21), Rutaceae (21), Solanaceae (21), Caryophyllaceae (20), Nyctaginaceae (20), Fabaceae (18), Amaryllidaceae (17), Moraceae (15), Ranunculaceae (14), Asteraceae (13), Lecythidaceae (13), Oleaceae (13), Apiaceae (11), and Rubiaceae (10). For details on species identity and references, see Knudsen et al.18

Ethylene biosynthesis and action

ACC synthase cDNA clones have been isolated from a large number of plant species (Arabidopsis, tomato, mung bean, winter squash, apple, tobacco, avocado, melon, orchid flower, carnation flower and peach). It has become clear that ACC synthases are encoded by a highly divergent gene family and that expression of the different isoforms is, in many cases, organ and stimulus specific (e.g. Rottmann et al., 1991 Olson et al., 1991 Mori et al., 1993). Using the antisense technique it was discovered that the tomato ripening related gene pTOM13 encoded a component of the ethylene biosynthesis route (Hamilton, Lycett & Grierson, 1990). Functional expression of the gene in yeast revealed that the gene encoded ACC oxidase (Hamilton, Bouzayen & Grierson, 1991). Comparison of the nucleotide sequence with other genes showed that the sequence shared significant homology with a flavanone 3-hydroxylase gene from petunia. This led to the development of methods to isolate the protein and study its...

Communication in flowers

Further investigations showed that auxin, which is known to be present in orchid pollinia, is able to induce ACC synthase gene expression in the stigma. Treatment with aminoethoxyvinylglycine (AVG), an inhibitor of ACC synthase activity, completely blocked the effect of auxin. This indicates that the observed expression of ACC synthase genes, in response to auxin, was mediated by ethylene. Pollination or auxin treatment presumably induces another, not yet identified, ACC synthase gene responsible for a first small increase in ethylene production (O'Neill et al., 1993).

Crassulacean acid metabolism allows plants to survive even during a very severe water shortage

Many plants growing in very dry and often hot habitats have developed a strategy not only for surviving periods of severe water shortage, but also for carrying out photosynthesis under such conditions. Cacti and the succulent ornamental plant Kalanchoe are examples of such plants, as are plants that grow as epiphytes in tropical rain forests, including half the orchids. As this metabolism has first been elucidated in Crassulaceae and involves the storage of an acid, it has been named crassulacean acid metabolism (abbreviated CAM). Important CAM crop plants are pineapples and the agave sisal, which provides natural fibers.

Multiple Origins of CAM

The CAM pathway has evolved polyphyletically many times in the plant kingdom and is currently found in approximately 16,800 species of 343 genera in 35 families, including terrestrial and aquatic angiosperms (monocots and eudicots), in addition to gymnosperms (Silvera et al. 2010). The more representative families of this syndrome are Aizoaceae, Asclepiadaceae, Asteraceae, Bromeliaceae, Cactaceae, Crassulaceae, Euphorbiaceae, Portulacaceae, and Orchidaceae. A survey of Brome-liaceae species showed that both CAM syndrome and epiphytic habit have evolved at least three times (Crayn et al. 2004). For Clusiaceae and Orchidaceae, multiple, independent CAM evolutions also occurred (Gehrig et al. 2003 Silvera et al. 2010). Although the original ecological pressure for the evolution of CAM was probably

Darwin Mendel and the Evolutionary Synthesis

Vergence supported and strengthened what Darwin formally called his theory of descent with modification. This theory was set forth in On the Origin of Species (1859). Darwin drew heavily on examples from the distribution of plants and on knowledge of plant breeding to formulate his theory. In the last twenty years of his life, he studied the phenomenon of adaptation in plants such as orchids, which had evolved spectacular contrivances by which to attract pollinators such as bees. Plants were in fact to provide Darwin with some of the best evidence in support of his theory.

Plant Diversity in Rain Forests

The great majority of plants in rain forests consist of dicotyledonous trees. For example, the genera Ficus (Moraceae) and Piper (Piperaceae) are diverse throughout the tropics, whereas Eperua (Caesalpiniaceae) and Shorea (Dipterocarpaceae) are species-rich in Neotropical and Asian forests, respectively. Some families that are herbaceous in temperate areas develop as woody trees in rain forests (e.g., Verbenaceae, Urticaceae, and Polygalaceae). Monocotyledons are less common but include palm trees, various herbs, orchids, and grasses. Abundant woody climbers (often dicotyledons) are characteristic of rain forest vegetation. Their broad stems may cover several kilo-

Ventilation In Micropropagation

Micropropagation is a mass vegetative plant propagation system on an artificial nutrient medium under a control sterile environment to ensure pathogen-free, true-to-type and rapid production. The notion that the micropropagation technique can play a vital role in the production of pathogen free propagation was realized since the development of the 'totipotency' theory of the cell in the early twentieth century. Nearly three decades have elapsed since George Morel first proposed the application of plant tissue culture for the commercial clonal propagation of orchids. However, like many new technologies, progress in micropropagation is not as rapid as many expected, even now, relatively few crops are being produced commercially (Lumsden et al., 1994). The major reasons for the slow commercialization are i) loss of plants due to microbial contamination, ii) poor growth and development of in vitro plants, iii)

Early or Northern Coralroot

This small fascinating orchid is uncommon in Unalaska and is easily overlooked because of its inconspicuous color. The coral-roots are saprophytic plants, deriving nutrients from decaying organic matter. Because of this they lack chlorophyll and hence the dark green color of most other plants that make their own food. The rootstock is a pale, brittle coral-like mass, actually an underground stem which sprouts new plants. It favors damp muddy or rocky soil, wetlands and meadows, and blooms in early to midsummer.

Time to petal wilting

The time between anthesis and visible wilting of the flowers may be long (2-3 weeks), as in chrysanthemum, short (about one week) such as in Iris, or very short such as in Hemerocallis fulva, where the time between flower opening and collapse is less than 24 h, hence its name daylily. The same is true for the species in which petal wilting is regulated by ethylene time to wilting ranges from long as in several orchids, to short as in carnations (not treated with STS), and to very short as in Ipomoea and Tradescantia. Regulation by ethylene or not, therefore, apparently has little relationship with flower longevity.

Interorgan signalling in flowers

A flower is a complex structure composed of several different organs, each of which has a variety of functions essential for successful reproduction. Pollination and, in orchids, emasculation often leads to rapid changes in flower parts distinct from the site of action thereby providing an excellent model to study the possible involvement of translocatable factors in the coordination of the post-pollination and post-emasculation events. In many species, pollination induces rapid changes in the perianth. This may include changes in pigmentation, senescence and abscission (Stead, 1992). In orchid flowers, emasculation (removal of the pollinia and the anther cap), which is a natural part of the pollination event, often has a comparable effect. Pollination- or emasculation-induced changes in pigmentation have been reported in flowers of Cymbidium (Woltering & Somhorst, 1990) and Lupinus albifrons (Stead & Reid, 1990) and examples of over 50 angiosperm families exhibiting subtle...

Recognition between the symbionts

A fact that complicates and tends to confuse our thinking about recognition is the remarkable absence of close specificity between the symbionts. There is however some specialization. For instance, Ericales have their own peculiar brand of mycorrhiza not found, to any extent, outside that order, with a few species of fungi which do not consort with other plants. The same is true in great measure of the Orchidaceae. On the other hand ectomycorrhiza formed by large numbers of coniferous and angiospermous trees and a few pteridophytes and very few herbs, with any of many species of basidiomycetes and ascomycetes, may also hold fungal species in common with arbutoid and monotropoid mycorrhizal plants. In neither the ectomycorrhizal plants nor those forming vesicular-arbuscular mycorrhiza is there a single example of a species of fungus restricted to a single species of host. There are cases of a single genus being restricted to a single family or genus of host, but most are of wide...

Carbon physiology of mycorrhizal symbioses

Green mycorrhizal hosts provide, by photosynthesis, all or most of the carbon compounds of their mycorrhizal system. By contrast, the chlorophyll-free hosts, e.g. Monotropaceae, some Orchidaceae as adults, all Orchidaceae as seedlings and the so-called saprophytes of other families, derive all their carbon compounds by the activity of their fungi. Indeed there are broadly two kinds of mycorrhizal fungi, with respect to carbon economy those of the green hosts have no or very limited capability of digesting and absorbing soil-borne carbon polymers, cellulose, pectins, lignin, etc. On the other hand, the fungi of chlorophyll-less plants may derive carbon by digesting such carbon polymers and translocating the products through their mycelium and releasing them to their hosts. These species of fungi belong to well-known ligninoclastic or cellulo-clastic species. Others are parasitic on other green plants or mycorrhizal with them, redistributing, as it were, carbon compounds by parasitizing...

Translocation in mycorrhizal systems

Translocation in orchid fungi was first investigated by S.E. Smith (1967), using orchid seedlings as receptors and the hyphae of species of Rhizoctonia as translocators. Carbohydrate absorbed by the fungus from the culture medium appeared in the hyphae as trehalose, and in some strains as mannitol also. In the seedling tissue these fungal sugars diminished and sucrose was formed, i.e. the reverse of the behaviour in ectomycorrhiza. Translocation over considerable distances in centimetres, of phosphate in particular, has been shown to occur in vesicular-arbuscular, ericoid, orchid and ectomycorrhizal fungi. Estimates of quantity per unit length per unit time for individual hyphae have been made, but they are often subject to some doubt, in particular instances because they depend on accurate estimates of the number of hyphae connecting the root or seedling to the source.

Rain Forest Structure

Rain forest structure is highly complex and determined by competition for light among plant species. Isolated trees, emerging above the canopy, are often present and can be 70 to 80 meters in height. Different tree species grow following various architectural models related to bud location and branching patterns and may or may not form distinct forest layers. Lianas rooted in the ground and epiphytes (e.g., ferns, orchids, and bromeliads) growing on support branches are common in the canopy. Leaves are often medium to large in size, lustrous, and tough. Their shape is often simple, ending with a drip tip to shed rainfall. Compound leaves are thought to represent an adaptation to rapid upward growth or seasonal drought and occur more commonly among plants growing in light gaps, in early succes-sional vegetation, or in tropical evergreen seasonal forests. Very little of the light falling on the canopy reaches the ground (0.5 to 2 percent of the illumination available in the canopy), so...

Unanswered Questions

Scientists are divided about how many species have been shaped by coevolution. Several important questions need to be answered before this issue will be resolved. If insects exert relatively little pressure on plants, how often would plant defenses change Do insects make mistakes in selecting plants as food or oviposition sites If not, how do they ever begin feeding on a new plant type How great a change is necessary to provoke a response in the coevolutionary partner for example, how much change in the shape of an orchid is necessary to provide improved visitation by an insect And how can we evaluate the importance of the coevolutionary partner versus other factors that influence the evolution of plants, animals, and microbes see also Evolution of Plants Interactions, Plant-Fungal Interactions, Plant-Plant Interactions, Plant-Vertebrate Pollination Biology.

Nemacladus rigidus

The tiny, slender-stemmed, profusely branched threadplant is so small that it is completely overlooked by the majority of visitors to the Southwest, yet it is one of the most common and most attractive of desert flowers. Under a magnifying glass, the shape and coloring of the minute, delicate flowers make them appear as beautiful as orchids. The white flowers are touched with tints of red, brown, yellow or purple.

Global occurrence

Epiphytes inhabit an unusually extensive biotope virtually every humid tropical forest contains them, sometimes in such great variety that single trees host dozens of species. Occurrence on drier sites is less common and usually involves fewer taxa, but not necessarily lower abundance certain Mexican and Peruvian cactus scrub forests, for instance, support dense populations of a few stress-tolerant bromeliads and orchids. Epiphytes are best represented on stable, relatively temperate sites where pre- and lower-montane, wet, and pluvial forest is well developed (Fig. 8.4 Table 8.6). Reasons for this as well as for their disproportionate presence in New as opposed to Old World tropical forests are discussed in Chapter 8. Frost, a powerful impediment to vascular epiphytism, sets different limits in the two hemispheres. Only a few bromeliads, ferns, and orchids penetrate higher American latitudes along marine coasts. Tillandsia usneoides (Fig. 7.2) and Polypodium polypodioides (Fig. 1.6)...

Water Dispersal

Seed germination and the establishment of the young plant is, of course, the only true sign of reproductive success. Dispersal without establishment is to no avail. In every case the rate of germination is critical. Many dias-pores do not fall into the proper situation for germination. Often large numbers of seeds are killed by a wide variety of beetles or weevils that specialize on seeds. Different species have developed various methods of survival. Some, such as orchids, produce thousands of minute seeds per capsule, giving some a good chance of success. Other species use the opposite strategy of producing large and heavy fruits with a lot of stored food material to ensure survival after germination. Some species, such as the seeds of the Beilschmiedia in the Lauraceae, have an increased chance of survival by having the seeds begin the germination process while still on the trees, where they are less susceptible to attacks. The red mangrove Rhizophora mangle (Rhizophoraceae) goes...

Botanical Work

Darwin's first book on plant evolution was titled Fertilization in Orchids (1862). He chose to study orchids because of the range of adaptations they displayed with respect to fertilization. Darwin recognized that these elaborate adaptations served to facilitate cross-pollination by insects such as bees. For this reason, cross-pollinated plants had flowers with bright colors and fragrant nectaries to attract bees and other insects, while wind-pollinated plants, which did not have to attract insect pollinators, had flowers with little or no color. The book on earthworms was published just six months before Darwin's death. Until his end, Darwin remained a productive scientist. Some of his most imaginative work was performed toward the end of his long life. His was a happy and productive life in a home filled with the voices of his ten children and numerous grandchildren. On his death in 1882, he received a rare honor for a scientist he was given a state burial and was buried at...

Seed Structure

A seed is a combination of maternal tissues, embryo tissues, and (in an-giosperms) endosperm tissue. Seeds of different species are variable in size and internal structure at the time they are shed from their parent plant. They may be barely visible to the naked eye (for example, orchids), weigh a few micrograms to milligrams (for example, poppy, tobacco, and many annual weeds), weigh up to several hundred milligrams to grams (for example, soybean, maize, pea, and bean) or even several kilograms (coconut and Lodoicea maldivica).

The Embryo

Several variations on this general theme occur. In the Brazil nut the cotyledons are much reduced and the bulk of the seed is occupied by a storage hypocotyl. Because the Brazil nut is primarily a single hypocotyl, it does not split in two like most other nuts made from two enlarged cotyledons. Cotyledons are absent from the seeds of many parasitic species. In orchids, seeds are shed when the embryos are extremely small and contain only a few cells, and completion of development occurs afterward.

Adaptive Traits

Desiccation tolerant arborescent monocotyledons form a remarkable example of convergent evolution. This type of arborescent monocotyledons occurs in both tropical and temperate regions and is found within Boryaceae (Borya), Cyperaceae (Afrotrilepis, Bulbostylis, Coleochloa, Microdracoides), and Velloziaceae (e.g., Vellozia, Xerophyta). They possess a number of ecophysiological and morphoana-tomical adaptations (e.g., roots with velamen radicum, Porembski and Barthlott 1995) that render them perfectly adapted for the colonization of rock outcrops. Besides their treelike habit, their ability to form clonal populations of considerable age (i.e., hundreds of years) by means of stolons or by basal branching allows for the long lasting occupation of suitable sites (for details see Porembski 2006). The trunks of arborescent Cyperaceae and Velloziaceae are regularly colonized by vascular epiphytes with certain orchids (e.g., Polystachya spp. in tropical Africa, Pseudolaelia vellozicola in...

Moisture procurement

Epiphytes native to all but the wettest forests or anchored in deep humus must either create sizable impoundments with their own bodies or meet all needs during occasional contact with canopy fluids. These latter PS species are poorly known in terms of moisture procurement. The exceptions - several atmospheric bromeliads, a few orchids, and some ferns - possess analogous absorptive devices. Although different organs and tissues are involved, a single type of architecture is common to all. In each case, mini-impoundment is based upon a biphasic system a superficial, nonliving, imbibing tissue overlying a deeper absorptive one containing transfer cells which traverse a vapor barrier. The two best-known absorptive aerial organs are the velamentous orchid root and the trichomed bromeliad leaf.

Island Biogeography

Have evolved to about 1,000 native species today, although some botanists who place greater emphasis on minor variations consider the number to be much higher. The Hawaiian flora is also considered to be disharmonious, meaning its species distribution differs from that of similar mainland regions. For example, only three native orchids are found on Hawaii, although one would expect many more because of the archipelago's tropical location and wide range of habitats. Conversely, the Campanulaceae (bluebell family) is the most speciose family in the islands, with 110 species of native plants. In other regions of the tropics, the family is an insignificant portion of the flora. see also Biodiversity Evolution of Plants Gray, Asa Orchidaceae.


Orchidaceae Orchid family In most monocots, the floral parts occur in multiples of three. One example is the tulip, which has six petals (often called tepals, since there is no clear differentiation of sepals and petals), six stamens, and a pistil with three chambers or locules, representing the three carpels. The pollen grains of monocots also differ from those of most dicots. In monocots, each pollen grain has just one thin-walled region, the colpus, which is the area from which the pollen tube emerges when the pollen grain germinates. Most dicots, in contrast, have three such regions. This thin area of the pollen wall often takes the form of a single elongate furrow, or sulcus, that extends most of the length of the pollen grain. see also Alliaceae Bamboo Dicots Evolution of Plants Grasses Orchidaceae Palms Systematics, Plant.

Pollen Maturation

And crucifers such as Brassica species and Arabidopsis possess dry stigmas with an epidermis of many large, hairy papillae cells interacting directly with pollen grains, to accept compatible pollen and reject pollen that is incompatible or from foreign species. The surface of papillar cells is covered with an interrupted layer of waxy cuticle overlaid with a distinct proteinaceous pellicle of poorly defined molecular composition (Ciampolini et al. 2001 Hiscock et al. 2002). However, wet stigmas often contain three distinct zones, namely an epidermis with papillae, a subepidermal secretory zone and a parenchymatous ground tissue. Legumes and members of the Orchidaceae and Solanaceae families are typical wet stigma-type plants. Most exudates are produced by the cells of the secretory zone, and less secretion is derived from the stigmatic papillae of wet stigmas at pistil maturity (Kandasamy and Kristen 1987). Moreover, pollen and stigma structures are largely coevoluted, since plants of...


Except for the orchids and some bromeliads and mistletoes, epiphyte seed physiology has never been intensively examined. Light often stimulates germination in canopy habitats, a process mediated via phytochrome in bromeliads (Benzing 1980) photosynthetic pigments appear to serve the same purpose for mistletoes. Only a tiny fraction of the canopy flora has been assayed, but seed longevity has so far proved to be modest - generally less than a year. Viability can be quite transitory some chlorophyllous Utricu-laria seeds perish within days under normal room conditions. Seed banks would seem to offer no particular advantage to epiphytes, and there is no evidence that they exist. Seed vivipary may be overrepresented in epiphytes (Araceae, Cactaceae, Gesneriaceae, and other fleshy-fruited taxa Madison, 1977). Aridity constitutes the major physical threat to early juveniles. Seedlings of most plants desiccate faster than adults simply because of their less favorable S V ratio and small...

Diversity of Flowers

Variations in fusion, arrangement, and symmetry of floral organs provide further diversity. Fusion between organs of the same whorl (coalescence) and fusion of organs from separate whorls (adnation) is common among many families of angiosperms. For instance, coalescence is seen in snapdragon (Antirrhinum, Scrophulariaceae) with the petals fused at the base, and adnation in tobacco (Nicotiana, Solanaceae) with stamens fused to the petals. Position of organ attachment to the receptacle also influences flower architecture. If the corolla and stamens attach to the receptacle below the ovary, the flower is referred to as having a superior ovary (e.g., Liriodendron tulipifera, Magnoliaceae). In contrast, having the corolla and stamens attach to the receptacle above the ovary produces a flower with an inferior ovary (e.g., Iris, Iridaceae). In radially symmetric flowers, termed actinomorphic, all organs within any particular whorl are identical and positioned equidistant from other organs...

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