Aeschynomene

Taxonomy

Aeschynomene C. Linnaeus Sp. Pl. 713. 1 Mai 1753.

Subfamily: Faboideae.
Phylogenetic Number: 3.14.09.
Tribe: Aeschynomeneae.
Subtribe: Aeschynomeninae.
Species Studied - Species in Genus: 21 studied; ca. 150 in genus.

Description

Fruit: A loment (or a loment segment); 0.8–2 cm long; 0.4–0.5 cm wide; 0.1–0.3 cm thick; length less than twice as long as width to 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx, or deciduous calyx; with calyx shorter than fruit (in loments that do not articulate); with orifice formed by curving of fruit or fruit segments, or without orifice formed by curving of fruit or fruit segments; straight, or curved (or slightlycurved), or S-curved, or 0.5-coiled, or 1-coiled, or 1.5-coiled, or 4-coiled, or 2-coiled; not plicate; not twisted; asymmetrical, or symmetrical; circular, or linear, or moniliform, or falcate; with 1 straight and 1 curved suture, or both sutures parallelly curved; narrowing in several places, resembling Desmodium (3.11.09) fruit; not inflated; compressed, or quadrangular; without beak; tapered at apex; aligned with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous, or fragile, thinner than chartaceous, like Trifolium; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin constricted, or not constricted; margin constricted along both margins, or constricted only on 1 margin; margin without sulcus; margin plain; wing(s) absent; stipitate, or substipitate; with the stipe 1–25 mm long; indehiscent. Replum occasionally visible. Loment an intact article; indehiscent; segments (articles) inconspicuous; segments (articles) 3–7 mm long; segments (articles) widest across seed area; segments (articles) with all essentially similar in shape; segments (articles) D-shaped, or rectangular. Epicarp dull; monochrome; black, or brown, or green (blackish), or tan; with surface texture uniform, or not uniform, with patches of different texture not restricted to the base and apex; glabrous, or pubescent and indurate; with hairs erect; with 1 type of pubescence; appressed puberulent, or tomentose; with pubescence gray; with pubescence uniformly distributed; with simple hairs, or glandular hairs; pliable; with hair bases plain; glandular (sections Aeschynomene and Ochopodium); with glandular hairs; without spines; smooth, or not smooth; with elevated features; veined, or not veined; obliquely veined relative to fruit length; not tuberculate; verrucose-rugose, or muricate, or faveolate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome; tan; smooth; without adhering pieces of testa; septate; with septa thicker than paper, firm; with septa eglandular; ligneous (sub); not exfoliating; remaining fused to epicarp; without wings; entire. Seed(s) 1–18; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus of 1 length only; thick; straight. Aril absent.

Seed: 1–6 mm long; 0.7–5 mm wide; 2–2.5 mm thick; not overgrown; not angular; asymmetrical; reniform; compressed; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; glossy; not modified by a bloom; colored; monochrome; black (and greenish), or brown (light); glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Raphe not visible. Hilum present; fully concealed; concealed by funicular remnant; with faboid split; with the lips of the faboid split the same color as the rest of the hilum, or lighter colored than the rest of the hilum and therefore conspicuous; larger than punctiform; 1.5 mm long; with curved outline; elliptic; marginal according to radicle tip, or between cotyledon and radicle lobe; flush; within halo; halo lighter than testa. Lens not discernible. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; not concealing radicle; split over radicle; with lobes; with lobes not touching; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis deflexed; perpendicular to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; lobe tip straight, or curved; deflexed and parallel to cotyledon width; centered between cotyledons; 1/2 to nearly length of cotyledons. Plumule rudimentary, or well developed; glabrous.

Distribution

Tropics to warm temperate America, Africa, and Asia.

New World, or Old World; pantropical to pansubtropical; United States to West Indies to Mexico to Central America to South America; Argentina, Peru, Brazil, Ecuador, and the Guianas; Madagascar to Africa to Indian Ocean to Southwest Asia to India to Indochina to China to Korea to Australia to Indonesia and the Philippines to Pacific.

Generic Notes

Rudd (1955) monographed the American species and according to her subgeneric categories, BARC has representatives of both subgenera and seven of eight series. The missing series included two species: A. fluminensis J. Velloso de Miranda and A. parviflora M. Micheli. Of the studied species only three are restricted to the Old World. Rudd also provided seed and fruit data for each American taxon. Verdcourt (1974) monographed Aeschynomene for the Flora of Zambia, and included seed and fruit data. Pandey and Jha (1989) reported on the seed structure of A. aspera C. Linnaeus (type for genus) and A. indica C. Linnaeus. Rudd (1955) recorded the variable epicarp surfaces of articles using these descriptors: (Hairs) appressed-pubescent, ciliate, crisp-pubescent, glabrate, glabrous, glandular-hispidulous, hispid, hispidulous, pubescent, sericeous, subappressed hairs, subglabrous, villous-hispid, white-pubescent; (surface) faveolate, muricate, muricate in center of article, reticulate-veiny, rugose, smooth, tuberculate, tuberculate bases of hairs..., veiny, ventricose, verrucose, and verrucose at center of article. All species of Aeschynomene are noxious weeds in rice (Oryza sativa C. Linnaeus) in Arkansas.

Tribal Notes

Tribe Aeschynomeneae

Rudd (1981a) recognized four subtribes of Aeschynomeneae: Ormocarpinae V.E. Rudd (genera 3.14.01–3.14.08), Aeschynomeninae (genera 3.14.09–3.14.16), Discolobinae (A.E. Burkart) V.E. Rudd (genus 3.14.17: Discolobium), Poiretiinae (A.E. Burkart) V.E. Rudd (genera 3.14.18–3.14.21), and Stylosanthinae (G. Bentham) V.E. Rudd (genera 3.14.22–13.4.26). Tribal and subtribal placement of Diphysa is based on Lavin (1987; Polhill, 1994a, 1994b), and not on Polhill and Sousa (1981), who placed Diphysa in Robinieae. Bailey et al. (1997), using the chloroplast rpl2 intron and ORF184, suggested that Brya (11.01), Cranocarpus (11.02), Phylacium (11.22), and Neocollettia (11.26) are not members of Desmodieae (11) and that they probably belong in Aeschynomeneae.