The genera Geranium and Pelargonium have remained confused for over 200 years, even after Linnaeus (1753) and his binomial system of classification. Both genera were then placed under the genus Geranium and although Sweet (1820) re-classified them under two genera, acceptance by the general public as well as nurserymen is still minimal.
The majority of plants sold as 'geraniums' in garden centres, shops and supermarkets are Pelargonium species and cultivars. There are however some Pelargonium cultivars sold as Pelargoniums at garden centres: these are the large-flowered Regal Pelargoniums. All the scented-leaf Pelargoniums, on the other hand, even those with large flowers, are almost invariably sold as 'geraniums'.
Most of the books about Pelargonium are mis-headed e.g. 'Geraniums' (Delamain and Kendall, 1987); 'Miniature and Dwarf Geraniums' (Bagust, 1988); 'Geraniums for home and garden' (Shellard, 1981). The only difference between genera is seen when books are entitled 'Hardy Geraniums' (Bath and Jones, 1994; Yeo, 1985), which signifies that the true Geranium genus alone will be involved. This is because Pelargonium species are not hardy plants and are not able to survive the weather in Europe, unlike the hardy Geranium species found everywhere in hedgerows, wastelands and rockeries.
Pelargonium species originate from South Africa and different species are found in distinct habitats. The Pelargonium species related to the Geranium oil-producing cultivars are mainly located in the Cape area. The first Pelargonium species, Pelargonium triste was brought over from the Cape to Leiden before 1600, then John Tradescant obtained the species in 1631 (Miller, 1996), following this, other species were brought over by various botanists for the next 300 years and hybridization became very rampant. This occurred especially during Victorian times, where almost every rich landowner had conservatories and glasshouses dedicated to the tender and rare plants, which included the novelty Pelargonium species.
There are numerous misnomers given for the origin of 'Geranium oil' in the dozens of 'Aromatherapy' books appearing during the last few decades, as well as some scientific reference books (Fenaroli, 1997). The worst misnomer shows the total misconception of the genus as in many aromatherapy books and journals, Geranium maculatum, Geranium robertianum and other Geranium species are implicated either directly or indirectly. This arose due to the unfortunate original mistake by aromatherapy book authors, who read up the medicinal properties of true 'geranium' from the many Herbals (Culpeper, 1653, 1835; Gezard, 1597; Grieve, 1937) and thought that those were attributable to the Pelargonium species.
For example, we have an amazing botanical concoction in this quote: 'The oil is extracted not from the familiar brightly coloured geranium but from the species Pelargonium Geranium Robert or "lemon plant" — which is very often displayed in abundance in Greek restaurants' (Worwood, 1991).
Tisserand (1985) informs us that: 'Pelargonium odorantissimum graveolens grows about 2 ft. in height, has serrated, pointed leaves, and small, pink, flowers. The whole plant is aromatic. It is found on wastelands, in hedgerows, and on the outskirts of woods. It was used by the ancients as a remedy for wounds and tumours.' He is undoubtedly referring to G. robertianum (Culpeper, 1835), as the quote is partly extracted from this source, and it continues: 'all geraniums are vulneraries but this herb more particularly so, only rather more detersive and diuretic, which quality is discovered by its strong, soapy smell'.
Another quote taken from Lawless (1992) again shows a lack of understanding of the origins of Geranium oil: 'The British plant herb Robert (G. robertianum) and the American cranesbill, (G. maculatum) are the most widely-used types in herbal medicine today, having been used since antiquity', as this has nothing to do with Pelargonium. In fact this statement is partly true, as the main usage of Geranium species is in herbal medicine, whilst that of the Pelargonium-derived 'geranium' oil is in perfumery, cosmetics and aromatherapy products. Furthermore, Geranium species are usually used as a tea or alcoholic extract which is taken orally; comparatively few external applications are mentioned and these again use the water-soluble or alcoholic extracts and not essential oils (EOs) (Culpeper, 1835; Grieve, 1937).
One of the misnomers most frequently used is 'Pelargonium odoratissimum or 'P. odorantissimum (Lawless, 1992; Valnet, 1984) and 'Pelargonium odorantissium (Westwood, 1991). Pelargonium odoratissimum is an actual species, with very small, white, apple-scented leaves (van der Walt, 1977), and not used for 'Geranium oil' production. The name 'Pelargonium odoratissimum' probably came from a particular P. graveolens variety as 'odoratissimum' i.e. it was not a true species but a very odoriferous variety. The name P. odoratissimum was then misquoted by Knuth (1912). The early writers about (EOs) (Guenther, 1950) as well as the trade distributors used the wrong name and it has been perpetuated by aromatherapists, who after all, are not botanists.
Another misnomer used is P. asperum: which is described as a cross between unknown parents (Knuth, 1912) and by Harvey (1860) as a garden variety of P. quercifolium (which has a camphoraceus smell). On the other hand, almost identical drawings are shown by Mastalerz (1982) for P graveolens (L'Heritier, 1792) and P. X asperum adapted from G. radula Roth, but to confuse the issue further, P. asperum Ehrhart ex Willd is in fact a hybrid between P. graveolens X P. radens.
Yet another name often used is P. roseum Willd. The problem is that Willdenov's Herbarium (1800) shows two identical plants: one is labelled as P. radula var. roseum and the other as P. graveolens var. roseum, but the description matches that of the hybrid P. radula X P. graveolens which shows once more that it is not a species.
A fourth misnomer is P. graveolens. This may be partly true for some Geranium oil originating in Africa (Ducellier, 1933), but this is doubtful as the species has a more distinctive peppermint aroma (Demarne and van der Walt, 1989; Lis-Balchin, 1991). However, the main source of the oil is from a cultivar known as P. cv. 'Rosé' which gives rise to the commercial 'Geranium oil, Bourbon' and originated from hybridization in England, probably in the eighteenth century, and the cultivar was then exported to the
History of nomenclature, usage and cultivation of Geranium and Pelargonium 7
South of France and Reunion and also lately to China. The 'Rosé' cultivar has been found to be, most probably, a hybrid between P. capitatum X P. radens (Demarne and van der Walt, 1989). The cultivars used for the production of Geranium oil in many parts of the world remain confused; in some papers originating in India, the cultivar is stated to be that obtained as a cutting from the cultivar 'Rosé' from Reunion, however, many papers state that their Geranium oil source is from P. graveolens.
The main usage of Geranium species is in herbal medicine, whilst that of the Pelargonium-derived Geranium oil is in perfumery, cosmetics and aromatherapy products. The production of commercial Geranium oil, from several Pelargonium cultivars, is now mainly in Reunion, Egypt and China; however the true sales of Geranium oil are greatly in excess of that derived from plants, due to the ever-increasing production of synthetic and 'nature-identical' Geranium oil. Geranium oil contains mainly citronellol and geraniol and their esters, therefore can be easily concocted from cheaper EOs and adjusted to the recommended ISO standards. The actual odour can be even more appreciated by perfumers than the real essential oil. Synthetic 'Geranium oil' also has a more potent antimicrobial activity (Lis-Balchin et al, 1996).
The pharmacological activity of the water-soluble extracts of the two genera are not very different: they both have a high proportion of tannins and have an antidiarrhoeal function (Watt and Breyer-Brandwijk, 1962). The lipophylic EOs of Pelargonium species have mainly a spasmolytic effect on smooth muscle, except for P. grossularioides, which was used as an abortifacient in southern African folk medicine (Watt and Breyer-Brandwijk, 1962) and has been shown to have a spasmogenic action on smooth and uterine muscle in vitro (Lis-Balchin and Hart, 1994).
Many Pelargonium species were used as folk medicines: herbal teas and extracts of leaves, tubers and roots were used (Watt and Breyer-Brandwijk, 1962) and one of these, Umckaloabo, from P sidoides or P. reniforme, is now commercially produced for use in respiratory ailments (Kolodziej and Kaiser, 1997; Kolodziej et al, 1995).
Pelargonium EOs from leaves of the many different species and cultivars (other than those grown to produce commercial Geranium oil) have very different odours and chemical compositions, but most of the floral-smelling ones act through cyclicAMP as the secondary messenger; others with odours which are more pine or menthol-like have a different mode of action (Lis-Balchin and Hart, 1998). There is therefore some correlation between their mode of action and their chemical composition. The antimicrobial effects have also been studied in vitro on a number of bacteria and in vivo as food preservatives, with promising results (Lis-Balchin etal., 1998a). The antimicrobial effect could not be directly correlated with the chemical composition so far (Lis-Balchin and Roth, 2000), although an inverse relationship was found between the amount of 1,8-cineole and antifungal activity (Lis-Balchin etal, 1998b). The DNA relationship with chemical composition has also been studied in a number of scented Pelargonium species and some correlation has become apparent (Piotrowski et al, 1999). This has alsoprovided another aspect of chemotaxonomy to add to the alkaloid chemotaxomy (Lis-Balchin, 1996, 1997; Lis-Balchin etal, 1996a).
The numerous aromatherapeutic uses for Geranium oil, both through massage and inhalation, are yet to be scientifically validated (Lis-Balchin, 1997a), although there is every reason to accept the scientific evidence that massage in itself can relax and that inhalation of a pleasant aroma and its action through the limbic system also has a relaxing effect (Buchbauer etal, 1991; Jellinek, 1954, 1956; Kubota etal, 1992; Manley, 1993; Stoddart, 1990; Torii et al, 1988; Vickers, 1996). Theoretically, this could lead to the acceptance that many stress-related conditions like dermatitis, asthma, intestinal problems and headaches could be alleviated by the use of Geranium oil.
True Geranium species were used in the past all over the world. G. maculatum or American cranesbill root was used as 'styptic, astringent, tonic, for piles and internal bleeding; excellent as an injection for flooding and leucorrhoea; taken internally for diarrhoea, childhood cholera, chronic dysentery and for gargling (Grieve, 1937)'. It contains tannins and is said to be effective against stomach ulcers and inflammation of the uterus and has possibilities in treating cancer (Chevallier, 1996).
Geranium species are used nowadays mainly in Japan, USA and also in eastern Europe. Geranium thunbergii, which is one of the most important medicinal plants in Japan (gen-noshouko) is used as an antidiarrhoeal folk medicine (Ishimaru and Shimomura, 1995). The use is the same therefore as that for many Pelargonium species in South African folk medicine (Watt and Breyer-Brandwijk, 1962). It contains a large concentration of phenolic constituents in the form of hydrolyzable tannins such as corilagin, geraniin and elaeocarpsin. Although elaeocarpsin has a high potential for tannin activity, as measured in combination with proteins e.g. collagen, gelatin, casein, haemoglobin, it shows little astringency. Due to this characteristic, which only slightly stimulates the alimentary canal, it is used for treating digestive diseases. It is also used for various other diseases (Nishioka, 1983) including psychotropic diseases (Ueki et al., 1985). Geranium has also shown antiviral action (Courtout et al., 1991).
Both Geranium and Pelargonium species have been reproduced using micropropagation and some success has been made in producing active components by tissue culture (Charlwood and Charlwood, 1991; Ishimaru and Shimomura, 1995). The means are there therefore for producing plants as well as new active components when they are discovered.
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