Rhynchosia caribaea (Jacq.) DC.
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Authority
Grear, John W. 1978. A revision of the New World species of Rhynchosia (Leguminosae-Faboideae). Mem. New York Bot. Gard. 31 (1): 1-168.
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Family
Fabaceae
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Scientific Name
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Description
Species Description - Herbaceous, slender vine to 4 m, from woody base, the stems twining, one to few, simple or branching, sulcated, angular (becoming terete wtih age), villous to villosulose, the hairs closely or loosely appressed. Stipules ovate-subulate or lanceolate, acuminate, villous, persistent, 24 mm long, 1-2.5 mm wide. Petioles slender, 1-4 cm. Leaflets 3, membranaceous or subcoriaceous, ovate-rhomboid or deltoid, acute or rarely obtuse or acuminate, base subtruncate, cuneate or widely rounded, 1.5-4.5 cm long, 1.5-4.5 cm wide, glabrate to sparsely strigulose above, glabrate, puberulous (restricted to veins) and gland-dotted beneath, terminal petiolule 6-14 mm, the laterals subobsolete to 2 mm, stipels lacking. Inflorescences equal to or usually exceeding the leaves, 5-15 cm, branching, flowers lax, peduncle 1-4.5 cm, pedicels 2-4 mm. Bracts ovate, abruptly acuminate, caducous, 2-3 mm long, 1.5-2 mm wide. Calyx not exceeding the corolla, villosulose, 6-8 mm long, tube 3-4 mm, lobes subulate, deltoid and acuminate, 1.5-4 mm, vexillar lobes extremely shallow, 0.5-1 mm. Corolla yellow, streaked purplish, 10-16 mm. Standard obcordate-rounded, glabrous, emarginate, with fleshy semi-circular ridge internally, 10-16 mm long, 8-9 mm wide, auricles 1-1.5 mm, claw 3-5 mm. Wings oblong, glabrous, 9-16 mm long, 2-3 mm wide, claw 2-3 mm. Keel blades falcate, glabrous, 10-16 mm long, 2.5-4 mm wide, claw 24 mm. Stamens 10-16 mm. Fruits falcate, compressed, gland-dotted and viscid-hirsute (the hairs 3-4 mm and yellowish), 2.5-3.5 cm long, 6-9 mm wide, beak 2-4 mm. Seeds ovate-reniform, compressed, brown, black or mottled, 4-5 mm long, 3-4 mm wide, hilum ovate, 1-1.5 mm. Strophiole lobes cuneate.
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Discussion
Glycine caribaea Jacquin, Collect. 1: 66; Icon. Pl. Rar. 1, t. 146. 1786. Rhynchosia gibba E. Meyer, Linnaea 7: 170. 1832. Copisma gibbum (E. Meyer) E. Meyer, Comm. Pl. Afr. Austr. 1: 137. 1836. Rhynchosia acuminata Ecklon & Zeyher, Enum. Pl. Afr. Austr. 2: 253. 1836. Rhynchosia gazensis Baker, Leg. Trop Afr. 2: 475. 1929. Type. Collected “Ex insulis Caribaeis ...” by Jacquin. Plate 146 in Jacquin’s “leones” (1786) is based on the type specimen. Despite the epithet, R. caribaea is native to Africa, ranging from the Cape Province of South Africa northward to southern Rodesia. It shows a great resemblance to R. minima, which also occurs in Africa and the two would appear from overall morphological similarities to be closely related. Rhynchosia caribaea, however, is distinguished by larger flowers and fruits and by viscid-hirsute pods. This is clearly stated in the original description by Jacquin (1786) and shown by his illustration. The misleading specific epithet once caused a great deal of taxonomic confusion in the New World due to the insufficient characterization of the species already present here. Rhynchosia minima, R. swartzii and R. edulis have all been identified in older collections as R. caribaea. In 1899, Vail suggested that R. caribaea probably didn’t occur within the U. S., but she did not venture an opinion as to its true identity or distribution, leaving the mystery to be solved by future botanists. This was accomplished 52 years later by Meikle (in 1951). According to him, the plant conforming to Jacquin’s type and description occurs naturally in southern Africa. I have also examined African material which, indeed, fits the description of R. caribaea. Meikle provides a historical account of the species and its nomenclature and gives the following explanation for the misleading name: “It must be remembered that Jacquin described R. caribaea from cultivated material, not from a dried specimen collected in the Caribbean area, and one can only assume that a misplaced label, or perhaps a faulty memory, was responsible for the erroneous localization, and for the misleading specific epithet.” He also cites a number of cultivated specimens which would seem to indicate its popularity as a greenhouse plant in botanical gardens in the late eighteenth and early nineteenth centuries. With one exception, the few sheets of R. caribaea examined by me and attributed to the New World are all old collections made from plants cultivated in European botancial gardens. One such collection at G is of interest. It is from the herbarium of Ventenat and consists of two sheets labeled “R. caribaea, Porto Rico.” However, it is a mixed collection—one sheet is R. caribaea and the other is R. minima. Considering the explanation of Meikle concerning the reasoning for the error in nomenclature, as well as the similarity and easy confusion of R. caribaea and R. minima, one might speculate that a specimen of R. caribaea from Africa was inadvertently mixed in with a Puerto Rican specimen of R. minima. Jacquin might have encountered a similar situation in examining the specimens on which he based Glycine caribaea. It is also interesting to note that R. minima is found in all the localities listed for R. caribaea in the New World—the Caribbean, the Orinoco River area and Florida. Meikle is also of the opinion that “no species of Rhynchosia agreeing with R. caribaea is to be found in the New World.” This may indeed be the case but I have found some evidence to the contrary. No recent collections of R. caribaea exist for the New World, but there is a single specimen at S collected in Puerto Rico by Sintenis in 1885, which has both vegetative and reproductive parts and is definitely R. caribaea. This might represent an early, stray introduction which did not become established in the New World. In the type description, Jacquin bases G. caribaea on cultivated plants grown from seed collected by him in the Caribbean. In describing and illustrating G. caribaea for The Botanical Register in 1818, Edwards states that it is “A West Indian species, introduced by Lord Petre about the year 1742. The plant from which the drawing has been taken, was raised from Jamaican seed.” In 1837, Macfadyen included R. caribaea in his Flora of Jamaica as being found at only one locality-“on fences, in the neighborhood of Bath.” There is no confusion with R. minima because that species is also listed as common in Jamaica. The description given by Macfadyen is characteristic of Jacquin's plant and he also points out its similarities to R. minima as well as its differences. The account of R. caribaea in Edward’s Botancial Register is also cited. In subsequent Jamaican floras (Fawcett & Rendle, 1920; Adams, 1972) reference is made to Macfadyen’s earlier report of the species in Jamaica but it is not listed as occuring there now. Although R. caribaea is no doubt native to Africa and is now confined there, it might have been introduced into the Caribbean in the past, as is thought in the case of R. minima, but unlike that species, it did not become a successfully established member of the American flora and only a few very old collections and reports remain. Therefore, as an alternative to the explanation given by Meikle, the possibility also exists that Jacquin might have collected the species in the Caribbean after all at one of the few places where it had become established in the islands—maybe even at the locality in Jamaica where it was seen by Macfadyen. It could simply be a matter of luck and that Jacquin was in the right place at the right time.
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Distribution
Distribution. Africa, with possible introduction into Jamaica and Puerto Rico.
Africa| Jamaica South America| Puerto Rico South America|