Eriosema rufum (Kunth) Don var. rufum

  • Authority

    Grear, John W. 1970. A revision of the American species of Eriosema (Leguminosae-Lotoldeae). Mem. New York Bot. Gard. 20: 1-98.

  • Family

    Fabaceae

  • Scientific Name

    Eriosema rufum (Kunth) G.Don var. rufum

  • Description

    Species Description - Stems to 1 m tall, rufo-pilose, the hairs broadly spreading. Stipules lanceolate, free, 6-8 mm long, 3.0-3.5 mm wide. Petioles 1.5-3.0 (-4.0) mm long. Leaflets oblong to ovate, obtuse, 3-6 (-8) cm long, 1.5-2.5 cm wide, short-pilose above and below, rarely glabrous, terminal leaflet somewhat remote from laterals. Inflorescences 2.0-3.5 cm long, not exceeding the mature, cauline leaves, peduncles 1-9 mm long, pedicels 2-3 mm long. Bracts ovate, 4-5 mm long, 2.5-3.0 mm wide. Calyx 5.0-5.5 mm long, tube 1.0-1.5 mm long, lobes 3.0-3.5 mm long. Corolla 8-10 mm long. Standard 9-10 mm long, 6.5-7.0 mm wide. Wings 8.5-9.0 mm long, 2.5-3.0 mm wide. Keel blades 9-10 mm long, 3.5-4.0 mm wide at maximum, claw 1.5-2.0 mm long. Stamens 8.0-8.5 mm long. Fruit 1.3-1.5 cm long, 6-7 mm wide. Seeds 4.5-5.0 mm long, 2.5-3.0 mm wide.

  • Discussion

    Glycine rufa H.B.K., Nov. Gen. & Sp. 6: 423. 1823. Venezuela, "locis humidis, prope Caripe et in Cerro del Cocollar, alt 400 hex (Nova Andalusia)." The type specimen, presumably a collection of Humboldt, could not be found.

    Rhynchosia rufa (HB.K.) DC., Prodr. 2: 384. 1825.

    Eriosema rufum (H.B.K.) G. Don, Gen. Hist. 2: 347. 1832.

    Eriosema rufum var glabrescens M. Micheli, Vidensk. Meddel. Kob. 1875: 92. 1875. Brazil, Minas Gerais, "Lagoa Santa: in campis." Holotype not seen.

    Eriosema domingense Urb. & Ekman, Ark. Bot. 22A(8): 49. 1929. Holotype examined (S): "Haiti, Massif du Nord prope C a rice ad Lamielle in pinetis ca. 450 m alt." Ekman H6195. W/o date. Isotype (US).

    Eriosema adulterinum Urb. & Ekman, Ark. Bot. 22A(8): 50. 1929. Holotype examined (S): "Haiti, Massif du Nord prope Carice inter Lamielle et Montagne-Organisee ca. 500 m alt." Ekman H6209. W/o date. Isotypes (A, F, K, NY).

    Local Names. Oreja de tigre (Venezuela: Bolivar); pegapega amarilla (Venezuela: Bolivar); yuguilla (Venezuela).

    Eriosema rufum var rufum exhibits only slight variation over its extensive geographical range, and this is primarily in the amount of indument on the leaflets as well as some variation in leaflet width.

    Urban and Ekman described a new species, E . domingense, from Haiti, but examination of the type shows it to be identical with E. rufum var rufum. Its presence in Haiti is not expected, for although this taxon is found widely distributed in northern South America, it is absent from Central America and the Greater Antilles with the exception of Haiti. Urban and Ekman have also established E. adulterinum from Haiti as being a natural hybrid species produced by the crossing of E. crinitum with E. domingense. The type description states that the pollen is deformed and of two different sizes. Examination of the type specimens shows somewhat more narrow leaflets than those usually encountered in E. rufum var rufum, but other than this variation in leaflet width, the type material of E . adulterinum exhibits no great differences from the typical variety of E. rufum. The nature of the pollen could not be confirmed inasmuch as the type specimens are sterile.

    Some of the variability in this instance may actually be due to sympatric introgression with E. crinitum, but considering the difficulty of recognizing the hybrids and proving that extensive stabilization of back-cross types has occurred, it is better to withhold formal taxonomic recognition for such entities for the present. Consequently E. adulterinum has been reduced to synonymy under E. rufum var rufum.

    As with the other species described originally by Humboldt and Bonpland, the type collection has not been found, but the plate of drawings and the description are considered adequate for identification of the taxon.

  • Distribution

    Distribution. Haiti and Trinidad in the Caribbean and from northern South America to Bolivia and central and southeastern Brazil (Fig. 17). Occurring in savannas, campos-cerrados, in open pine forests, near streams, pastures, usually on sandy soils; at elevations of 70-1200 m.

    Haiti South America| Trinidad and Tobago South America| Bolivia South America| Brazil South America| Peru South America| Ecuador South America| Colombia South America| Venezuela South America| Guyana South America| Suriname South America| French Guiana South America|