Rhynchosia pyramidalis (Lam.) Urb.
-
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.
-
Family
Fabaceae
-
Scientific Name
-
Description
Species Description - Herbaceous or suffrutescent vine to 4 m,the stems one to several from woody rootstock, branching, twining, angled (becoming terete with age), villosulose (the hairs silvery or yellowish) becoming glabrate. Stipules lanceolate, acuminate, densely villosulose, caducous, 2-3 mm long, 0.5-1 mm wide. Petioles villosulose, 2-8 cm. Leaflets 3, thin-coriaceous, elliptic to ovate, acuminate, base obtuse or rounded, 3.5-13 cm long, 2-8.5 cm wide, glabrous above, gland-dotted and silvery-villosulose beneath, terminal petiolule 7-30 mm, the laterals 2-5 mm, stipels lacking. Inflorescences elongate, exceeding the leaves, 8-30 cm, branching, flowers lax, peduncle 1-5 cm, pedicels 1-2 mm. Bracts lanceolate or linear-lanceolate, long-acuminate, caducous, 4-7 mm long, 0.5-1.5 mm wide. Calyx not exceeding the corolla, villosulose, 5-6 mm, tube 2-2.5 mm, lobes widely lanceolate, acute to acuminate, 24 mm, vexillar sinus 1 mm. Corolla yellow, veined with purple, 8-10 mm. Standard obovate to orbicular, emarginate, gland-dotted and villosulose, 8-10 mm long, 6-8 mm wide, auricles 0.5-1 mm, claw 1.5-3 mm. Wings oblong, glabrous, 8-10 mm long, 3-3.5 mm wide, claw 2-3 mm. Stamens 8-9 mm. Fruits ovate, plump, deeply constricted, brown or blackish, densely puberulous, becoming glabrate with age, gland-dotted, 1.3-2.4 cm long, 7-9 mm wide, beak 2-3 mm. Seeds subreniform with pronounced radicular lobe, red with black spot at one end, plump, 5-7 mm long, 4-5 mm wide, hilum linear, 2 mm, strophiole lobes linear.
-
Discussion
Dolichos pyramidalis Lamarck, emend. Grear. Dolichos pyramidalis Lamarck, Encycl. 2: 296. 1786, pro parte quoad typum. Rhynchosia phaseoloides var precatoria (DC.) Grisebach, Cat. Pl. Cub. 74. 1866, pro parte. Dolicholus phaseoloides (Swartz) Millspaugh, Fieldiana Bot. 2: 53. 1900. Dolicholus pyramidalis (Lamarck) Britton & Wilson, N. Y. Acad. Sci. 5(3): 415. 1924, pro parte. Type. Collected in “ . . . Lisle de Saint-Domingue . . ” by Plumier. No exact locality or collection specified. A drawing of Plumier is based, in part, on the type specimen. Local Names, fruta de pitillo, John Crow bead (Guatemala); bejuco culebra (Cuba); bejuco de paloma, peronías (Puerto Rico); bejuco pegapelo (Dominican Republic); pimande, pimangué guatabe (Haiti); coralito, tasanpulga (Mexico: Oaxaca); ojitos de picho (Mexico: Tabasco). Rhynchosia pyramidalis, along with R. phaseoloides and R. erythrinoides, are the only members of series 3 to be found in the Caribbean, where they are sympatric. Due to their superficial similarities and sympatric occurrence, they have frequently been collected together and described as one species. However, they are quite distinct and I have found absolutely no intermediates. It would be safe to assume, therefore, that hybridization does not occur to blur the characters that serve to separate them. Even though the characters useful for distinguishing them are not identical, they are sufficiently similar to cause confusion if they have not been thoroughly investigated. From the numerous mixed collections I have seen, this is obviously the case. The confusion can be partially traced back to Lamarck (1786). His description of Dolichos pyramidalis, based on polynomials of Tournefort (1700) and Plumier (1703), is too general to distinguish any one species group and his comment that Plumier found the plant in Santo Domingo (Hispaniola) is of no value since all three occur there. The Plumier description (“Phaseolus florum spica pyramidata, semine coccineo nigra macula notato”) is also too broadly defined and examination of copies of Plumier’s drawings at BM, K and OXF based on this collection show what appears to be elements of all three species. To compound the confusion, in 1788 Swartz used the name Glycine phaseoloides for a mixed collection of his own and based it as well on the same polynomial of Plumier cited by Lamarck for Dolichos pyramidalis. Swartz also cited a polynomial of Browne (1756) which is also too general for use in distinguishing the species. In 1806 Swartz provided a more complete diagnosis of Glycine phaseoloides in which elements of at least two of the three species are described. Confusion notwithstanding, both R. pyramidalis and R. phaseoloides have been in use for many years, and rather than reject them, it is possible from the available information to emend the original type descriptions of both and choose a lectotype for G. phaseoloides from the available syntypes collected by Swartz. Dolichos pyramidalis Lam., the basionym for R. pyramidalis, is herein emended so that the species can be easily characterized using the description and illustration (Fig. 10) provided. Three sheets of the type collection by Swartz of Glycine phaseoloides (at S) have been examined. Two are mixtures of R. pyramidalis and R. phaseoloides. The sheet which is wholly R. phaseoloides has been designated the lectotype and the original description of the basionym (G. phaseoloides) is emended elsewhere herein to conform to the lectotype. In 1821, Sims (in Curtis’s Botanical Magazine) was the first to attempt to clear up the confusion between the two elements. Glycine phaseoloides is clearly described and illustrated and both Lamarck’s binomial and Plumier’s polynomial are doubtfully listed in synonymy but with the following comment: “It is probable that Plumier’s plant the Dolichos pyramidalis of Lamarck is not the same species with the present subject, being described as having racemes of flowers a foot and half in length; Swartz describes them as four or five inches long, in other respects his description coincides nearly with our own.” The third confused species was characterized, typified and named R. erythrinoides by Schlechtendal & Chamisso in 1830. In 1918, Urban attempted to distinguish between R. pyramidalis and R. phaseoloides in the West Indies but only succeeded in bringing about utter chaos. The characters he chose for separating the two (pertaining to the bracts and seeds) do not work for a very simple reason: his descriptions are based unknowingly on R. erythrinoides as well. As a result, Urban only further added to the confusion by discussing three different elements as though they were two. He also placed R. precatoria in synonymy under R. pyramidalis, although the former is a perfectly good species occurring in Mexico and Central America. It is therefore not surprising that even now any species of Rhynchosia producing red and black seeds has been placed in either R. pyramidalis or R. phaseoloides. Fortunately, Urban cited numerous collections, which he referred to either one species or the other. Examination of these sheets shows both groups to be composed of R. pyramidalis, R. phaseoloides and R. erythrinoides. In some cases, duplicates of the same collection are of different species and in others there are different species mounted on the same sheet. Rhynchosia phaseoloides var precatoria is also a mixed collection of these three different elements. In making the combination Dolicholus pyramidalis, Britton & Wilson (1924) include characteristics of the three different species in their description. The confusion surrounding these species continutes to persist but R. pyramidalis is easily distinguished from the other two Caribbean species by a combination of the following characters: a unique seed outline with a pronounced radicular lobe (sensu Polhill, 1976), the seed with a narrowly lanceolate hilum and almost entirely red except for a small black area at one end of the seed and mostly elliptic leaflets which are glabrate on their upper surfaces.
-
Distribution
Distribution. Greater Antilles, eastern Mexico, Guatemala, Belize and Honduras (Fig. 11). Occurring in woods and thickets on hillsides, in open areas, by streams and roadsides and on hedges, at lower and middle elevations to 610 m.
Mexico North America| Guatemala Central America| Belize Central America| Honduras Central America| Cuba South America| Dominican Republic South America| Haiti South America| Jamaica South America|