Cajanus

Taxonomy

Cajanus M. Adanson Nom. cons. Fam. 2: 326, 529 ('Cajan'). Jul-Aug 1763.

Subfamily: Faboideae.
Phylogenetic Number: 3.10.73.
Tribe: Phaseoleae.
Subtribe: Cajaninae.
Species Studied - Species in Genus: 13 studied; 31 in genus.

Description

Fruit: A legume; unilocular; 1.3–9.5 cm long; 0.6–1.4 cm wide; 0.2–0.3 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with persistent corolla, or deciduous corolla; with keel petal and standard petal; with persistent calyx, or deciduous calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight, or curved (slightly); not plicate; not twisted; asymmetrical; falcate, or linear, or moniliform, or irregular; with both sutures parallelly curved, or both sutures unequally curved, or both sutures nearly straight; not inflated; compressed; without beak, or with beak; declined; with solid beak the same color and texture as fruit; tapered at apex, or short tapered at apex; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin plain; wing(s) absent; nonstipitate; with all layers dehiscing, or indehiscent; splitting along suture(s). Dehiscence of valves along both sutures; assumed apical and down; active; with valves twisting. Replum invisible. Epicarp dull; monochrome, or multicolored; mottled; brown; with brown overlay (with light brown overlay); mottling color combination variable; with mottling over seed chambers; with surface texture uniform; pubescent and indurate; with hairs appressed; with 2 types of pubescence, or 3 types of pubescence; with pubescence golden; with pubescence uniformly distributed; with simple hairs and glandular hairs, or simple hairs, glandular hairs, and complex hairs; with bristle-like hairs; stiff; with hair bases swollen and plain; straight; straight at apex; glandular; with glandular dots, or dots and hairs; without spines; smooth; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; 1-layered; without balsamic vesicles; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; white, or tan, or brown; smooth; without adhering pieces of testa; septate; with septa thin (tissue paper-like), flexible; with septa eglandular; chartaceous; exfoliating in part; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 2–9; length parallel with fruit length, or transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 1 mm long; of 1 length only; flattened; hooked. Aril present, or absent; fleshy (if fleshy, also hard), or dry; when fleshy 2-lipped rim-aril, or hippocrepiform rim-aril; entire; covering less than 1/2 of seed; when dry 2-lipped rim-aril, or hippocrepiform rim-aril; entire; covering less than 1/2 of seed; without tongue (or flap) on lips of 2-lipped rim-aril, or with tongues (or flap) on lips of 2-lipped rim-aril; with 2 tongues or flaps, 1 on each lip of 2-lipped rim-aril, or 1 tongue or flap on 1 lip of 2-lipped rim-aril; ivory, or cream, or tan.

Seed: 3.4–9 mm long; 2.8–8.5 mm wide; 1.7–6.3 mm thick; not overgrown; not angular; symmetrical; oblong to circular to reniform; terete; with surface smooth; 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, or glossy; not modified by a bloom; colored; monochrome, or bichrome, or mottled, or streaked (in literature); with frequent mottles; reddish brown, or cream, or black (nearly), or gray, or white, or orange, or purple; with brown overlay; glabrous; smooth, or not smooth; with recessed features; pitted with small separate pits; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; partially concealed, or fully concealed, or visible; concealed by aril; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform; 0.3–4.5 mm long; with curved outline; elliptic; apical according to radicle tip but marginal according to seed length; flush, or raised; within rim; rim color darker than testa. Lens discernible; 0.5–1 mm long; with margins straight; linear; not in groove of raphe; confluent with hilum; flush; dissimilar color from testa; darker than testa; dark brown; not within corona, halo, or rim. Endosperm absent. 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; partially concealing radicle; notched at radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; white to tan; inner face flat; glabrous on inner face. Embryonic axis oblique; oblique to length of seed, or parallel to length of seed, or perpendicular 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 moderately developed and well developed; glabrous.

Distribution

Africa throughout Asia to Australia and Oceania and cultivated (1 species).

Old World; Africa to Madagascar to Southwest Asia to China to Indian Ocean to India to Indochina to Indonesia and the Philippines to New Guinea to Australia to Pacific.

Worldwide crop.
 

Generic Notes

Also included is Atylosia R. Wright & G.A.W. Arnott (10.73) which van der Maesen (1986) submerged into Cajanus, and the species count is from van der Maesen and not Lackey (1981). Van der Maesen discussed the relationships of Dunbaria and Cajanus (10.73). He included six species of Dunbaria in synonymies of various species of Cajanus. Endomallus pellitus F. Gagnepain and E. spirei F. Gagnepain are Cajanus goensis J.M. Dalziel according to van der Maesen. Cajanus is widely cultivated throughout the tropics with 85 percent of its production in India (van der Maesen and Somaatmadja, 1989; Purseglove, 1968). On the Indian subcontinent, it is used mainly as dried seeds or pulse, and elsewhere fresh seeds and pods are also commonly consumed.

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.