Opercular opening

FIG 14. General fruit characteristics of neotropical Lecythidaceae as illustrated by Lecythis, a genus with dehiscent fruits: A, Lateral view of the fruit of L. ampla (operculum removed, Mori 316); B, Distal view of the fruit of L. ampla (operculum removed, Mori 316); C, Operculum of the fruit of L. ampla (Mori 316); D, Operculum of the fruit of L. pisonis f.Mori 399), note the persistent columella; E, Seed of L. minor (Mori 423).

---calycine ring pedicel scar line of opercular dehiscence

---calycine ring line of opercular dehiscence opercular ring courbaril L. (Janzen, 1975) and Stemmadenia donnell-smithii Woodson (Mc-Diarmid et al, 1977). The mucilage may be distasteful or somewhat toxic or, more likely, it may gum up the mouthparts of any insect attempting to prey upon the fruit. Further field studies are needed to determine the extent of mucilage producing ducts in the Lecythidaceae and their adaptive value.

Structure of the Seeds

Two features of the seeds of neotropical Lecythidaceae are especially important in the taxonomy of the group: 1) the embryo type and 2) the nature of the funicle-aril.

1. Embryo type. In the Lecythidaceae three embryo types can be recognized on the basis of cotyledon structure.

a. Bertholletia or macropodial type. No cotyledons are differentiated. The bulk of the embryo consists of hypocotyl with cotyledonal tissue, if present, reduced to small scales at the apex of the embryo. Grias, Allantoma, Corythophora, Eschweilera, Lecythis and Bertholletia possess this type of embryo (Figs 17L, 18C, M, R). Old World Lecythidaceae with the same embryo structure are Barringtonia and Careya.

b.Gustavia type. Fleshy plano-convex cotyledons are present. Only Gusta-via has this type (Fig 15).

c. Couroupita type. Leaf-like cotyledons are present and the radicle is long. Cariniana, Couratari, and Couroupita have this embryo type (Figs 17D, H, 19F). Planchonia, a member of the Old World subfamily Plan-chonioideae, also has this embryo structure.

According to Duke (1969, Fig 66), the cotyledons of Cariniana pyriformis Miers have a complex circinate venation and are palmately lobed (Fig 17D). His observations need further confirmation from other species of the genus.

Alternately arranged cataphylls are present between the cotyledons and the eophylls (first leaves with green, expanded lamina) in at least Gustavia, Lecythis, Bertholletia and Eschweilera (Figs 15A, 16G, 17L, 18C). They are probably also present in the remaining genera, but we have not yet examined sufficient material to make a definitive statement. Duke (1969) states that cataphylls are absent in Couratari. However, his drawings indicate that he was examining the hypocotylar region rather than the region between the cotyledons and the eophylls where cataphylls normally occur.

In all species with foliaceous cotyledons that we have observed, the cotyledons are withdrawn from the seed coat upon germination (phanerocotylar cotyledons; Duke, 1969). However, Duke (1969) reports the presence of cryptocotylar as well as phanerocotylar cotyledons in Couratari. We have never observed cryptocotylar cotyledons in Couratari and believe that his Figure 61 illustrates phanerocotylar rather than cryptocotylar cotyledons. In Duke's Figure 61 the opposite arrangement of the leaves" and the absence of cataphylls below these "leaves" indicates that they are cotyledons rather than eophylls (Duke, 1969). Until more data indicate otherwise the cotyledons of all neotropical Lecythidaceae with foliaceous cotyledons must be considered plianerocotylar.

In genera with macropodial embryos, the germinating embryo may penetrate the seed coat at opposite ends of the seed (e g Lecythis minor Jacq., Fig 17L; L. tuyrana Pittier, Fig 19C; Bertholletia excelsa, Fig 18C; Eschweilera pittieri R. Knuth, Fig 18R) or less frequently at opposite sides of the seed (Eschweilera section Jugastrum, Figs 18M, 19D). In some cases the seed coat splits along one side and is carried upward with the growing stem until it drops off (Lecythis tuyrana, Fig 19C).

The three embryo types of the neotropical Lecythidaceae are paralleled in the Myrtaceae. Keys to the genera of New World Myrtaceae (e g McVaugh, 1956; Amshoff, 1958) often present a first dichotomy between embryo types, i e the foliaceous cotyledons of subtribe Myrciinae versus the plano-convex or undifferentiated cotyledons of subtribe Eugeniinae. The embryos of the third subtribe, the Myrtinae, are incurved with elongate radicles and minute cotyledons, a type not found in neotropical Lecythidaceae. The occurrence of all three embryo types of the New World Lecythidaceae in the Myrtaceae may indicate common ancestry rather than convergent evolution.

2. Structure of the funicle-aril. The seeds of neotropical Lecythidaceae are attached to the ovary wall in the following ways:

a. With no apparent organ of attachment, i e sessile. Gustavia superba (Kunth) Berg and G. speciosa (Kunth) DC. as well as most Eschweilera species west of the Andes do not have developed funicles and arils.

b. By a well developed funicle and no aril. Gustavia august a L. has a yellow tortuous funicle but no apparent aril (Fig 15E).

c. By a funicle surrounded by a fleshy aril. Lecythis usitata Miers exemplifies this type (Fig 17K). This type is also found in most species of Eschweilera east of the Andes.

The position of the funicle-aril is of taxonomic importance. In all species that we consider to belong to Lecythis, the funicle-aril is basal (Fig 17K), while in Eschweilera it is usually lateral (Figs 180; 19E).

d. By an aril completely surrounding the seed. We have observed this arrangement in one species of Eschweilera sect Jugastrum (Prance & Mori et al 24357, Fig 18I-L). In addition to the unusual aril this species has lateral germination (Figs 18M, 19D).

e. By an aril flattened to form a wing. Cariniana has a unilateral wing (Fig 17C), and Couratari a wing which surrounds the seed (Fig 18F).

Seeds with fleshy arils, sarcotestas, and wings are also present in the Meliaceae (Pennington and Styles, 1975). The diverse seed structure of these ecologically important families suggest that generic evolution in tropical trees has been promoted by different dispersal agents. Further support for the importance of dispersal agents in the adaptive radiation of tropical plants is given by Ducke (1948). He has cited many good examples of adaptations for dispersal by water, wind, or animals in closely related taxa of Amazonian plants.

New World Lecythidaceae are adapted for dispersal by a wide variety of animals, by water or, in Cariniana and Couratari, by the wind.

The orange mesocarps of Gustavia superba and G. grandibracteata Croat & Mori are eaten by animals. Once the exocarp is broken the orange color of the mesocarp serves to attract mammals which in turn scatter the seeds while eating the mesocarp. Humans also consume the mesocarps of G. superba and G. speciosa in Panama and Colombia respectively. Fish may play a role in dispersal of the riverine species, G. augusta, for seeds have been found in fish intestines by Prance (unpublished field data) and Honda (1974).

The seeds of Bertholletia excelsa are dispersed by scatter-hoarding rodents. At maturity the fruits drop to the ground, retaining the seeds because the opercular opening is too small to permit their release. Agoutis gnaw through the woody pericarp to remove the seeds. Those seeds which are not immediately eaten are cached, and some of the cached seeds are forgotten and left to germinate (Huber, 1909; Prance, unpublished field data).

We have confirmed Greenhall's (1965) observation that the seeds of Lecythis usitata are dispersed by bats. After dehiscence of the operculum the seeds hang from the base of the fruit by cord-like funicles that are surrounded by a large, fleshy, sweet tasting aril and are available to dispersal agents (Figs 17K; 19A-B). Bats remove the funicle-aril with the seeds attached and, after eating the former, drop the intact seeds at their roosts or while in flight. Monkeys may play a negative role in seed dispersal of L. usitata. While collecting in the Rio Cuieiras region (Amazonas, Brazil), Prance heard a distant banging noise in the forest. When asked what it was the local guide explained that the sound was made by monkeys opening fruits of the Sapucaia Nut Tree ( = L. usitata). This was confirmed by following the sound to a large tree of L. usitata (Prance et al 17970) where monkeys were observed opening fruit. The ground was strewn with seeds, arils, and pyxidia, the latter showing bruise marks resulting from the banging process. Many of the seeds were partially eaten thereby indicating that monkeys are seed predators of L. usitata.

The relative importance of monkeys as seed predators and/or dispersal agents is not yet known. Marc van Roosmalen (pers. comm.) informs us that the fleshy funicle-aril of L. poiteaui Berg is eaten by monkeys, especially Chiropotes satanas (Hoffmannsegg) and A teles paniscus (L.). He adds that the funicle-arils are so thoroughly harvested by these monkeys that he was unable to "collect untouched ones despite all possible efforts." Van Roosmalen (pers. comm.) has also discovered that monkeys of the genera Pithecia and Chiropotes are able to open fruit of Lecythidaceae before dehiscence with their well developed canine teeth. His observations suggest that these monkeys are specialized Lecythidaceae fruit eaters. However, their role as dispersal agents and/or predators is unknown for it depends on the stage of seed development when the fruit is opened and on what part of the fruit is eaten. We await the results of van Roosmalen's two-year study of monkey-plant interactions in Surinam to answer these questions.

The fruit of several species of Eschweilera are opened by parrots and macaws. In a tree of a species of Eschweilera (Prance et al 23804), many parrots were observed pecking out the seeds. However, more than half of the seeds were dropped to the ground relatively undamaged. This species produced abundant fruit during the 2 years it was observed (1974, 1975). In another species of Eschweilera (Prance et al 25502), a pair of macaws were observed feeding on the seeds and scattering many intact seeds on the ground. In a tree of another species of Eschweilera (Mori & de Granville 8828), macaws were observed opening the nearly mature fruits. Many seeds and partially damaged fruits covered the ground under the tree. All of the seeds on the ground were without arils and some seeds were damaged. To one of us (Mori) the arils tasted good but the mesocarp and seeds were very bitter, leaving an after-taste for several hours. From these three examples it is apparent that parrots and macaws serve as dispersal agents and/or predators of Lecythidaceae. Further observations are needed to determine the role that large birds play in the seed dispersal of Lecythidaceae.

Water dispersal occurs in several riverine species of Lecythidaceae. Asteranthos brasiliensis Desf. is restricted to the Rio Negro region of Colombia, Venezuela, and Brazil where it is abundant in blackwater flooded forests on sandy soil. The persistent calyx (Fig 16A) serves as a flotation device for the water dispersed fruits (Ducke, 1948). Another Amazonian riverine species, Allantoma lineata (Martius ex Berg) Miers, has water dispersed seeds which are released during the river's annual crest. After fruit dehiscence the seeds drop directly into the water where they float because of their high oil content (Ducke, 1948). Flotation experiments demonstrate that seeds of A. lineata float for at least 3 months (Prance, unpublished data). It is probable that other common riverine species of Lecythidaceae are hydrochorous.

The seeds of species of Cariniana and Couratari are dispersed by wind. The aril, which is normally thick and fleshy in other genera and serves to attract animals, is here flattened to form a wing (Figs. 17C, 18F). Trees of both genera are mostly either emergent or riverine and, therefore, expose their fruits to maximum wind velocities.

Generic Review

Asteranthos brasiliensis

The fruits of this monotypic genus are characterized by a persistent calyx (Fig 16A-D) that serves as a flotation device (Ducke, 1948; see discussion of seed dispersal above). The mature fruit contains a single ovate seed.

The seed is unlike any other species of Lecythidaceae in that the embryo is surrounded by copious, ruminate endosperm (Fig 16C, D). The embryo, although described by Knuth (1939c) as tubular, has two membranous cotyledons at the apex and a curved lower portion which gives it an overall "J" shape (Fig 16C).

The seed structure of A. brasiliensis supports Knuth's (1939c) treatment of A. brasiliensis as a monotypic family (Asteranthaceae) rather than as a member of Lecythidaceae subfamily Napoleonaeoideae (Niedenzu, 1892; Thompson, 1927; Pichon, 1945).

G. grandibracleato

FIG 15. Seeds and seedlings of selected species of Guslavia: A, Seedling of G. dubia (Dressier srt), note cataphylls between cotyledons and first leaves; B, Enlarged cataphyll from A, note minute stipules; C, Seed of G. hexapetala (Nee & Mori 4190), note remnant funicle and slight bulge above the funicle which represents the caruncle; D, Seedling of G. augusta (Nee & Mori 4209), note cataphylls along stem; E, Seed of G. augusta (Nee & Mori 4209), note expanded funicle; F, Seed of G. grandibracteata (Mori 836), note scar where seed was attached and apparent lack of a funicle.

G. augusta

Gustavia

The fruits of this genus have indehiscent pericarps, and the seeds are released when the pericarp is eaten by animals or when it rots away. We have also observed that seeds of Gustavia augusta sometimes germinate while still within the pericarp. Although Woodson (1958) and Corner (1976) report that Gustavia has dehiscent fruits, our field observations confirm that the fruits are indehiscent. In some species, eg G. brachycarpa and G. longifuniculata, the opercular areas may be weaker than the remainder of the pericarp. Consequently, in these species the opercular area is often removed by animals but in no case does it fall spontaneously.

Costate pericarps, which are present in several species, are especially well developed in species of section Hexapetala (figs 16F, 43). Although useful in specific classification, costae must be used with some caution for both costate and ecostate fruits may appear in the same population (e g G. dubia on El Llano-Carti road, Panama). Mesocarp color is a useful, but little recorded, character of Gustavia fruits. The mesocarp is yellow-orange in some species (e g G. superba and G. grandibracteata) and white in others (e g G. fosteri and G. dubia). Mesocarp color may be an adaptation to attract animals that eat the mesocarp and in turn disperse the seeds.

The fleshy, plano-convex cotyledons of Gustavia (Fig 15) are unique in the family. The funicles are well developed and contorted in some species (e g G. augusta, Fig 15E), inconspicuous and straight in others (e g G. hexapetala, Fig 15C), and apparently lacking in still others (e g G. grandibracteata, Fig 15F). In no species have we seen an aril that envelops the funicle. However, we have observed that mature seeds of G. hexapetala (Nee <$ Mori 4190} are sometimes surrounded by a whitish film that may be an aril which attracts animals for seed dispersal. The seeds of some species have a slight bulge near the hilum that is slightly different in color from the remainder of the seed coat (e g G. dubia). In our descriptions of the seeds of Gustavia this structure is referred to as a caruncle.

Our observations of the seedlings of G. augusta and G. dubia demonstrate that the cotyledons remain within the seed coat upon seed germination (haustorial) and that they are positioned above the ground (epigeal) Fig 15A, D). The lower part of the stem of the seedlings bears 4-10 cataphylls, each provided with a pair of minute stipules at its base (Fig 15B). The first true-leaves (eophylls) also possess small, white, caducous stipules.

Grias

The fruits of this genus have indehiscent pericarps which become pulpy at maturity and contain a single seed (Fig 16N). The fact that the pulp is edible suggests that animals play a role in seed dispersal.

The seeds lack cotyledons, i e the embryo is undifferentiated or macropodial.

Observations on the fruits of G. cauliflora (Guppy, 1917) show that the seeds of this species germinate quite readily when they fall into fresh water but

Lecythidaceae

FIG. 16. Fruit, seed, and seedling characteristics of Asteranthos, Guslavia, Allantoma, and Grias: A-D, Asteranthos brasiliensis (Prance et aI ¡5481): A, Entire fruit, note the persistent calyx; B, Lateral view of the seed; C, Longitudinal section of the seed showing the tubular embryo embedded in copious endosperm; D, Cross section of the seed showing the tubular embryo and the ruminate endosperm; E-H, Guslavia spp: E, Fruit of G. superba (Mori 837); F, Fruit of G.

FIG. 16. Fruit, seed, and seedling characteristics of Asteranthos, Guslavia, Allantoma, and Grias: A-D, Asteranthos brasiliensis (Prance et aI ¡5481): A, Entire fruit, note the persistent calyx; B, Lateral view of the seed; C, Longitudinal section of the seed showing the tubular embryo embedded in copious endosperm; D, Cross section of the seed showing the tubular embryo and the ruminate endosperm; E-H, Guslavia spp: E, Fruit of G. superba (Mori 837); F, Fruit of G.

that the embryos are killed by salt water. The pericarps are frequently encountered in the drift on Jamaican beaches (Guppy, 1917) and have been observed in the drift on San Jose Island, Panama (Johnston, 1949, plate 12, fig 4 as unidentified "seed"). The disjunct population of G. cauliflora on Jamaica (Fig 59) might be explained by chance long distance dispersal over salt water. Because this species grows in riverine habits, a large enough number of fruits are carried to the Caribbean and it is probable that one or more seeds may have reached Jamaica from Central America without being killed by salt water.

We have not been able to recognize interspecific differences in the fruits of Grias.

Allantoma lineata

The fruits of this monotypic genus are cylindric and have 4-5 locules and freely falling opercula. (Fig 161-J).

The embryo is undifferentiated.

The seeds are notched at the base and have a rugulose seed coat that is finely pitted (Fig 16K). The high oil content of the seeds permits them to float and aids in water dispersal (Ducke, 1948).

Cariniana

The fruits of this genus are obconic, obovate, or cylindrical, have 3 locules, and freely falling opercula (Fig 17A-B).

The seeds have unilateral wings that facilitate dispersal by wind, The wing is the flattened aril through which passes the vein-like funicle (Fig 17C).

The embryo possesses two foliaceous cotyledons (Fig 17D).

Couroupita

The fruits of this genus are round and indehiscent, have 6 locules and a 6-segmented pulp which turns bluish-green upon exposure to the air (Fig 17E-H). At maturity they fall intact and often split on impact with the ground. We have observed natives of the Amazon basin feeding the pulp to chickens and suggest that feral animals disperse the seeds.

Professor H.-W. Koepcke (pers. comm.) observed a tree of Couroupita guianensis in Amazonian Peru with many fruits on the ground around its trunk. The tree was observed over a three week period during which no animals touched the fruit although there were many rodents around. When he was about to cease daily observation a herd of wild pigs came past the tree and broke open, destroyed and ate all the fruits under the tree. Professor Koepcke brachycarpa fPittier 5269), note the winged (= costate) exocarp; G, Seedling of G. augusla (Nee & Mori 4194); H, Seed of G. augusta (Nee & Mori 4209), note the fleshy funicle; I-K, Allantoma lineata (Prance et al 11618): I, Base of fruit; J, Operculum; K, Seed with attached funicle-aril, note notched base of seed; L-M, Grias neuberthii (Boeke22U); L, Entire fruit; M, Apex of fruit showing remnant calyx lobes and style; N, Seed.

Cariniana Pyriformis

FIG 17. Fruit, seed and seedling characteristics of Cariniana, Couroupita, Lecythis, and Cory-thophora: A-C, Cariniana micrantha (Krukoff 5095); D, C. pyriformis, redrawn from Duke (1969): A, Base of fruit; B, Operculum; C, Winged seed, the wing is a flattened aril with the funi-cle passing through it; D, Apex of seedling showing the foliaceous cotyledons. E-H, Couroupita guianensis (E-G, FrOes 1705; H, Mori & Kallunki 3263); E, Entire fruit; F, Cross section of fruit believes that the seeds are thus dispersed by the swine who make only occasional visits to the Couroupita trees during their long foraging treks through the forest.

The seeds are lenticular and have a hairy covering which arises from the seed coat. The embryo possesses two foliaceous cotyledons (Fig 17H).

Corythophora

The fruits of this genus are campanulate or cylindric, have 4 locules, and freely falling opercula (Fig 17M-P).

The seeds are attached by a basal, erect funicle that is surrounded by a fleshy aril. The embryo is undifferentiated.

Bertholletia excelsa

The fruits of this monotypic genus are round, have 4 locules and an inwardly falling operculum which is smaller in diameter than the seeds (Fig 18A-C).

The strongly 3-angled seeds with their thick, indurate, rugose seed coats are unique in the family (Fig 18B). We have observed no funicle or aril in Bertholletia. The embryo of this genus is undifferentiated.

Several workers have suggested that there are two species of Bertholletia, one in which the operculum falls into the fruit and another in which it falls out of the fruit (Miers, 1874; Young, 1911; see discussion of uses in this monograph). We have found no support for this claim and therefore recognize only B. excelsa.

The fruit and seed structures of this genus are apparently adaptations for seed dispersal by scatter-hoarding rodents (see above discussion on seed dispersal).

Couratari

The fruits of this genus are cylindrical, have 3 locules and freely falling opercula (Fig 18D-G).

The seeds are unique in the family in that they are surrounded by a wing which represents a flattened membranous aril (Fig 18F). The wing is penetrated by the funicle which surrounds the seed. The winged seeds of Couratari, like Cariniana, are adapted for wind dispersal. In both genera the wings of the seeds are derived from arils but the position of the wing is different, being unilateral in Cariniana and surrounding the seed in Couratari.

showing the 6 pulpy segments; G, Longitudinal section of fruit showing seeds embedded in pulp; H, Apex of seedling showing foliaceous cotyledons; I-K, Lecythis usitata (I-J, Prance el a120210; K, Prance el a!24363); L, L. minor (Prance 23171); I, Base of fruit with attached pedicel; J, Operculum; K, Seed, note funicle surrounded by fleshy aril; L, Seedling; M, Corythophora rimosa (Prance et al 23518); N-P, C. alia (Prance & Ramos 23312): M, Base of fruit; N, Base of fruit; O, Operculum; P, Seed.

Bertholletia Excelsa

FIG 18. Fruit, seed, and seedling characteristics of Bertholletia, Couratari, and Eschweilera: A-C, Bertholletia excelsa (A-B, Prance et a! 16599; C, Prance blaslogeny coll. no. 4); A, Entire fruit; B, Seed; C, Seedling; D-F, Couratari guianensis (Maguire & Cowan 39318); G, C. stellata (Mori et al 9160): D, Base of fruit; E, Operculum; F, Seed; G, Seedling showing flattened stem and folia-ceous cotyledons; H-O, Eschweilera spp: H-M, Eschweilera sp section Jugastrum (H-L, Prance et

The embryo possesses two foliaceous cotyledons and the stem of the seedling is often flattened (Fig 18G).

Eschweilera

The fruits of this genus have 2 locules and freely falling opercula (Fig 18H-R).

The seeds have a lateral funicle-aril (Fig 18 O), or an aril which completely surrounds the seed (Fig 18I-L), or no funicle or aril. The embryo is undifferentiated, and in most cases the germinating seed penetrates the seed coat at opposite ends (Fig 18R). However, in those species that have wedged-shaped seeds surrounded by an aril the germination is lateral, i e the seedling penetrates the seed coat at opposite sides (Figs 18M, 19D). Species with seeds possessing the latter array of characters have been segregated from Eschweilera as the genus Jugastrum (Miers, 1874; Knuth, 1939b). Nevertheless, we feel that the similarity of flowers of Eschweilera and Jugastrum argues against their separation. Consequently, we have retained Jugastrum within Eschweilera and will recognize the above differences at the subgeneric level in our forthcoming treatment of the genus.

Lecythis

The fruits of Lecythis have 4 locules and freely falling opercula (Fig 171-L). In addition, some species of Lecythis (e g L. pisonis, L. usitata, L. ampla) have the largest fruits known to occur in the family.

The seeds are attached to the placenta by a straight funicle which is surrounded by an enlarged, white, fleshy aril. The funicle-aril of Lecythis is basal (Fig 17K) rather than lateral as in most species of Eschweilera. The embryo is undifferentiated, and at germination the seedling penetrates the seed coat at opposite ends (Fig 17L). After germination the seed coat may persist on the seedling until it rots away or it splits longitudinally and falls off (Fig 19C).

Fruit size and shape, although useful as interspecific taxonomic characters, must be used with some caution because of intraspecific variation (Dugand, 1947; Mori, 1970; Prance and Mori, 1978).

In summary, evolution of the fruits, seeds, and seedlings of the genera of New World Lecythidaceae has resulted in the following differences:

1. Indehiscent vs dehiscent fruits. Fruits of Gustavia, Grias, and Couroupita are indehiscent, whereas those of the remaining genera are dehiscent. Indehiscent fruits usually fall intact from the tree, and dehiscent ones remain on the tree until after the seeds have been dispersed. The correlation of indehiscent fruits with unspecialized flowers suggests that in-

al 24357; M, Prance et al 23397): N, E. odora (Mori et at 8727); O, Eschweilera sp (Mori et ai 9098); H, Entire fruit; I, Lateral view of seed; J, Cross section of I; K, Lateral view of seed; L, Cross section of K; M, Seedling showing lateral germination; N, Two different lateral views of the seed of E. odora; O, Lateral view of the seed of Eschweilera sp; P-R, Eschweilera pittieri (Mori & Kallunki 2830): P, Basal view of the fruit; Q, Lateral view of the fruit; R, Seedling.

Lecythidaceae

FIG 19. Fruit, seed, and seedling characteristics of Lecythis, Eschweilera, and Couroupita: A, Lecythis usitata, the operculum of the uppermost fruit has fallen (Prance et aI 24363); B, L. usi-lata, fruit without the operculum, showing the seeds attached by the funicle-aril (Prance et al 24363); C, L. tuyrana seedling showing the macropodial embryo (Mori & Kaliunki 1705); D, Eschweilera section Jugastrum showing lateral germination (Prance & Ramos 23397); E, Eschweilera sp showing the lateral funicle-aril (Mori et al 8727); F, Couroupita guianensis showing the foliaceous, phanerocotylar cotyledons (Mori& Kaliunki3263).

FIG 19. Fruit, seed, and seedling characteristics of Lecythis, Eschweilera, and Couroupita: A, Lecythis usitata, the operculum of the uppermost fruit has fallen (Prance et aI 24363); B, L. usi-lata, fruit without the operculum, showing the seeds attached by the funicle-aril (Prance et al 24363); C, L. tuyrana seedling showing the macropodial embryo (Mori & Kaliunki 1705); D, Eschweilera section Jugastrum showing lateral germination (Prance & Ramos 23397); E, Eschweilera sp showing the lateral funicle-aril (Mori et al 8727); F, Couroupita guianensis showing the foliaceous, phanerocotylar cotyledons (Mori& Kaliunki3263).

dehiscent fruits should be considered primitive in the New World Lecythidaceae. A special example of "functional indehiscence" is found in Bertholletia exceisa. In this species the operculum dehisces, but the seeds are retained within the pericarp until after the fruit falls to the ground because the size of the opercular opening is smaller than the diameter of an individual seed. Our studies of floral structure and leaf anatomy indicate that B. exceisa is most closely related to species of Lecythis, and, therefore, the "functionally indehiscent" fruits of Bertholletia probably evolved from ancestors with dehiscent Lecythis-like fruits.

2. Fleshy vs woody pericarps. Some species of Gustavia and Grias have relatively soft pericarps which are eaten by animals. The woody pericarps of the remaining genera apparently do not serve to attract animals but instead protect the developing seeds from animal predation.

3. Thick vs thin pericarps. The indehiscent fruits of species of Couroupita have relatively thin pericarps which tend to split open when the fruit falls, thereby revealing the pulpy mesocarp to animals which may disperse the seeds. Significant differences in pericarp thickness are found within a genus. For example, Cariniana pyriformis and C. micrantha (Fig 17A) have very thick pericarps in relation to overall fruit size whereas the pericarps of other species (cf C. estrellensis) are thinner. Thick pericarps probably give more protection to the developing seeds from animal predation.

4. Presence vs absence of mucilage. Mucilage-producing ducts are present in the pericarps of some species of Lecythidaceae (e g Lecythis chartacea). The mucilage may help protect the developing seeds from insect damage by being somewhat toxic or by gumming up the insects' mouthparts when they try to chew through the pericarp.

5. One vs several to many seeds per fruit. Asteranthos brasiliensis and all species of Grias have only one seed per fruit whereas the remaining genera have several to many seeds.

6. Presence vs absence of a funicle or a funicle-aril. Asteranthos brasiliensis, all species of Grias, and some species of Gustavia and Eschweilera lack apparent funicles and arils. Some taxa such as Gustavia augusta have a well developed tortuous funicle but no aril (Fig 15E). In contrast, all species of Lecythis and most of Eschweilera have a funicle which is surrounded by a fleshy aril (Figs 17K, 18 O). The presence of a fleshy aril usually indicates that animals eat the aril and in turn disperse the seed. However, two genera, Cariniana and Couratari have membranous, wing-like arils which are adaptations for wind dispersal.

7. Position of the funicle-aril. The funicle-aril may be basal as in all species of Lecythis (Fig 17K), lateral as in some species of Eschweilera (Figs 18 O, 19E), or completely surround the seed as in other species of Eschweilera (Fig 18I-L). Consequently, the position of the funicle-aril is often a useful taxonomic character.

8. Embryo type. The embryos of Grias, AUantoma, Bertholletia, Corythophora, Lecythis and Eschweilera are undifferentiated, i e lack cotyledons. In the genera with differentiated embryos the cotyledons are fleshy and planoconvex in shape in species of Gustavia, foliaceous in species of Cariniana, Couroupita, and Couratari, or small, membranous, translucent, and at the apex of a tubular, curved hypocotyl in Asteranthos.

9. Germination. Upon germination, seedlings which arise from undifferentiated embryos may penetrate opposite ends (e g Bertholletia, Fig 18C; Lecythis, Fig 17L; Eschweilera, Fig 18R) or opposite sides (e g Eschweilera, Figs 18M, 19D) of the seed coat. Sometimes the seed coat remains until it rots away or falls from the embryo (Fig 19C).

In seedlings that arise from differentiated embryos, the cotyledons may remain within the seed coat (e g Gustavia, Fig 15A) or be withdrawn from the seed coat (e g Couroupita, Fig 17H; Cariniana, Fig 17D; Couratari, Fig 18G) upon germination.

10. Flattened vs terete seedling stem. Seedlings of species of Couratari differ from species of other genera in that the hypocotyl is flattened instead of terete (Fig 18G).

Many of the fruit, seed, and seedling features of New World

Lecythidaceae can be attributed as adaptation to specific dispersal agents. For example, the "functionally indehiscent" fruits of Bertholletia excelsa are adapted for rodent dispersal, the fleshy aril of Lecythis usitata is an adaptation for bat dispersal, the flattened, wing-like arils of Cariniana and Couratari are adapted for wind dispersal, and the oily seeds of Allantoma are adapted for water dispersal. Continued field observations may demonstrate that other features such as number of seeds, position of the funicle-aril, embryo type, and germination type may have some adaptive significance.

V. POLLEN by J. Muller

The genera described in this part of the monograph all possess the Lecythis main pollen type (Figs 20, 21) as defined by Muller (1972). This is characterized by tricolpate pollen in contrast to the Planchonia main type which is syntricolpate. The colpi in the Lecythis main type are generally provided with more or less distinct endoapertures (Fig 20:4). The pollen grains of Asteranthos and Grias have indistinct endoapertures, mostly developed as equatorial constrictions only. Such grains may be termed colporoidate. In some species of Gustavia the endoapertures are well developed as thinned areas in the nexine and these grains are colporate. Shape is generally sub-prolate, occasionally spherical, size varies between 24 and 44 /im.

Exine structure of the genera described here is rather similar and consists of an inner nexine, generally of uniform thickness, a layer of columellae which are rather indistinct in Asteranthos, Allantoma and Cariniana, but more pronounced in Grias where the columellae may be arranged in a reticulate pattern in conformity with the surface sculpture of the tectum. The latter varies between perforate, reticulate, fossulate and perforate-verrucate. In some species of Grias the reticulate pattern is coarser on the poles. Asteranthos is characterized by reticulate-fossulate grains (Fig 21:1), perforate-reticulate grains occur in Allantoma (Fig 21:2) Cariniana (Fig 21:3-6), and Grias (Fig 20:1-2), while perforate-verrucate grains are found only in Gustavia (Fig 20:6).

The evolutionary significance and further interpretation of the pollen morphology of Lecythidaceae will be given in the second part of this monograph, after the pollen of all neotropical genera has been studied. In the meanwhile descriptions of all genera treated in this part are given below.

1. Asteranthos (Fig 21:1)

Material investigated: Asteranthos brasiliensis, Ducke 57a.

Tricolpate, suprolate-prolate, 33-37 /m.

Colpi fairly long, no distinct endoapertures present, although a slight equatorial constriction may occur. Colpus membranes with scattered small verrucae.

Exine thick, columellae short, fine, spaced in a duplicolumellate pattern underneath muri, tectum evenly reticulate-fossulate, muri fairly wide.

Pollen

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