Rhynchosia macrocarpa Benth.

  • 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

    Rhynchosia macrocarpa Benth.

  • Description

    Species Description - Herbaceous or suffrutescent vine, 4-5 m, from woody, branched rootstock, the stems twining or sprawling, one to several, branching, angular, becoming terete with age, villous (often becoming puberulous). Stipules ovate, acute, villous, caducous, 5-7 mm long, 1.5-2 mm wide. Petioles stout, 1-5 cm, villous. Leaflets 3, coriaceous, widely ovate, acute, base obtuse to cordate, 3-11 cm long, 1.6-6 cm wide, rugose, finely strigose and sparsely gland-dotted above, villous and densely gland-dotted beneath, terminal petiolule 5-20 mm, the laterals subobsolete to 3 mm, stipels linear, 2-3 mm. Inflorescences elongate, far exceeding the leaves, multiflorate, 15-25(-40) cm, often widely branched, flowers lax, peduncle 4-12 cm, pedicels 2-5 mm. Bracts broadly ovate, acute, caducous, 5-8 mm long, 3-5 mm wide. Calyx much shorter than the corolla, hirsute, 8-9.5 mm, tube 44.5 mm, lobes lanceolate, acuminate, 4-5.5 mm, vexillar sinus 2 mm. Corolla yellow, 1.5-2 cm. Standard widely obovate, emarginate, gland-dotted and hirsutulous, 2-2.4 cm long, 1.5-1.8 cm wide, auricles 1-2 mm, claw 4-5 mm. Wings oblong, sparsely hirsutulous at apex, 17-18 mm long, 4-5 mm wide, claw 3-4 mm. Keel blades falcate, sparsely hirsutulous at apex, 19-20 mm long, 8-9 mm wide, claw 6-7 mm. Stamens 20-22 mm. Fruits oblong-falcate, puberulous and hirsute intermixed, compressed, 20-22 mm long, 7-12 mm wide, beak 2-5 mm. Seeds reniform, dark brown, compressed, 5-7 mm long, 3-5 mm wide, hilum ovate, 1-1.5 mm, strophiole lobes cuneate.

  • Discussion

    Dolicholus macrocarpus (Bentham) Rose, Contr. U. S. Natl. Herb. 10: 101. 1906. Type. MEXICO. Aguas Calientes, Hartweg 58, Apr 1839 (holotype, K!; phototypes, C!, NY!, US!; isotypes, BM!, G!, GH!, K!, LE!, NY!, P!). Local Names. Frijolín, frijolillo (Mexico: Sonora). This species is most likely to be confused, at least superficially, with R. discolor in series 4, but differences in pubescence and calyx and fruit characters are usually sufficient to separate the two. Rhynchosia macrocarpa occurs primarily in northern Mexico, while the typical variety of R. discolor is mostly in southern Mexico and Central America. Rhynchosia discolor var lanceolata is found within the range of R. macrocarpa but it has a restricted distribution within that range and possesses more narrow leaflets.

  • Distribution

    Distribution. Northern to central Mexico (Fig. 23). Occurring in wooded ravines, in shrub-covered hills, in canyons in mountainous areas and among rocks in grasslands, often on soils of volcanic origin; at elevations of 1725-2500 m.

    Mexico North America|