Butea

Taxonomy

Butea W. Roxburgh ex C.L. von Willdenow Nom. cons. Sp. Pl. 3: 917. 1802.

Subfamily: Faboideae.
Phylogenetic Number: 3.10.04.
Tribe: Phaseoleae.
Subtribe: Erythrininae.
Species Studied - Species in Genus: 2 studied; 2 in genus.

Description

Fruit: A legume; unilocular; 10–18 cm long; 3–5.3 cm wide; 0.4–0.6 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical; samaroid; with both sutures unequally curved; not inflated; flattened; without beak; rounded at apex to truncate at apex; oblique with longitudinal axis of fruit; tapered at base to rounded at base; oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous and leathery; seed chambers externally visible; margin not constricted; margin without sulcus; margin embellished; margin with thickened sutural areas (especially dorsally), or wing(s); wing(s) present; wing(s) 1; wing(s) 30–53 mm wide (and 90–110 mm long); wing(s) samaroid; wing(s) basal; nonstipitate; indehiscent. Replum invisible. Epicarp dull; monochrome; tan; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; pilose to tomentose; with pubescence golden; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; veined; reticulately veined; not tuberculate; exfoliating in part; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 3-layered; without balsamic vesicles; without fibers; without reniform canals; with solid layer over spongy layer over solid layer; coriaceous. Endocarp present; visible; dull; opaque; mottled; tan; with mottling more or less uniform (dark and fine); with brown overlay; smooth; without adhering pieces of testa; nonseptate; chartaceous; exfoliating in part; remaining fused to mesocarp and epicarp; with wing(s) extending into epicarp; entire. Seed(s) 1; length parallel with fruit length, or oblique to fruit length. Funiculus 4 mm long; thick; straight. Aril absent.

Seed: 24–38 mm long; 19–27 mm wide; 5–6 mm thick; not overgrown; not angular; asymmetrical; irregularly reniform; flattened; with surface wrinkled; without visible 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; dull; not modified by a bloom; colored; mottled; with frequent mottles; reddish brown; with brown overlay (dark); glabrous; not smooth; with elevated features; wrinkled, or wrinkled and warty; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe visible; from hilum to near base of seed and terminating; not bifurcating; color of testa; raised. Hilum present; visible; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform; 1.5–2.5 mm long; with curved outline; elliptic; marginal according to radicle tip; recessed; within halo; halo darker than testa. Lens not discernible. Endosperm absent. Cotyledons not smooth; wrinkled; 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; partially concealing radicle; notched at radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis right angled, or oblique; perpendicular to length of seed, or oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear; lobe tip straight; deflexed and parallel to cotyledon width, or oblique to cotyledons; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

India.

Old World; India, Indochina, and Indonesia and the Philippines.

Generic Notes

Butea was revised by Sanjappa (1987) who recognized two species, not the four species of Lackey (1981). Ridder-Numan (1995) and Ridder-Numan and Van Der Ham (1997) considered this genus to be closely related to Meizotropis (10.06) and Spatholobus (10.05) and to Kunstleria in Millettieae (7).

Tribal Notes

Tribe Phaseoleae

Bruneau et al. (1995) carried out cladistic analyses of tribe Phaseoleae using chloroplast DNA restriction site data. Their results indicated that the tribe is not monophyletic and that the tribal delimitations between Phaseoleae and Desmodieae (11) and between Phaseoleae and Millettieae (7) are problematic.