Subfamily: Faboideae.
Phylogenetic Number: 3.27.07.
Tribe: Crotalarieae.
Species Studied - Species in Genus: ca. 200 studied; ca. 600 in genus.
Fruit: A legume; unilocular; 0.3–12 cm long; 0.3–1.7 cm wide; 1–2 cm thick; 2–9 times longer than wide, or more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx, or persistent 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, or symmetrical; oblong, or elliptic (clavate, oblong, or circular), or linear (and linear-oblong), or circular; with 1 straight and 1 curved suture, or both sutures parallelly curved; widest near middle or D-shaped; inflated (some species markedly inflated); terete, or compressed (especially species in subgenus Priotropis (R. Wight & G.A.W. Arnott) C.D.F. Meisner); without beak, or with beak; straight; with solid beak the same color and texture as fruit; rounded at apex to short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; rounded at base; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous, or coriaceous; seed chambers externally invisible; margin not constricted; margin with sulcus, or without sulcus; margin plain; wing(s) absent; stipitate, or substipitate, or nonstipitate; with the stipe 0.1–30 mm long; with all layers dehiscing, or indehiscent (for a few species); splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves enrolling, or twisting. Replum invisible. Epicarp dull; monochrome; brown to tan; with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent, or tomentose, or villous, or sericeous, or peltate; with pubescence brown (and including purple and blackish-brown); with pubescence uniformly distributed, or with apical pubescence different from basal pubescence; with apical 1/4 tomentose and basal 3/4 glabrous; with simple hairs; pliable; with hair bases plain; eglandular; without spines; smooth, or not smooth; with elevated features; not veined; not tuberculate; shagreen; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; coriaceous to ligneous (sub). Endocarp present; visible; dull; opaque; monochrome; brown, or tan; smooth, or hairy; without adhering pieces of testa; with hairs restricted to sutures, or in longitudinal rows, or scattered over endocarp; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 10–80; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.5–3 mm long; of 1 length only; filiform, or thick; S-curved, or curved. Aril absent, or present (rarely); dry; when dry rim-aril (in section Chrysocalycinae (G. Bentham) E.G. Baker subsection Stipulosae (E.G. Baker) F.A. Bisby & R.M. Polhill); entire; covering less than 1/2 of seed; brown, or tan.
Seed: 1–8 mm long; 1–6 mm wide; 0.75–3 mm thick; not overgrown; not angular to angular; asymmetrical; reniform (and obliquely reniform), or mitaform, or cordate (obliquely), or circular (sub); compressed, or flattened; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; with deep hilar sinus, or with shallow hilar sinus, or 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; usually glossy, or dull; not modified by a bloom; colored; monochrome, or mottled and streaked, or bichrome (primarily dark reddish-black with a white patch over radicle tip and with or without white patch at junction of radicle and cotyledon lobes or a continuous white patch to radicle tip to radicle cotyledon junction, C. spectabilis A.W. Roth); with frequent mottles; with frequent streaks; brown (in combination with most other colors), or tan, or yellow, or orange, or red, or black, or cream, or gray, or green, or purple; with black overlay, or brown overlay (greenish, yellowish, or reddish); glabrous; smooth, or not smooth; with elevated features, or recessed features; rugose (faces and/or margins), or shagreen, or warty, or wrinkled, or papillate; punctate (minutely punctate in C. stolzii (E.G. Baker) R.M. Polhill); coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or partially concealed, or fully concealed; concealed by radicle lobe (partially or completely concealed), or funiculus, or wing; with faboid split, or without faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform, or punctiform; 0.1–6 mm long; with curved outline; elliptic; between cotyledon and radicle lobe; recessed; within rim and within halo, or within rim, or not within corona, halo, or rim; halo lighter than testa; rim color darker than testa. Lens discernible (not bearing elevated features that rest of testa may bear and often with a light-colored longitudinal medial line); 0.5–1.5 mm long; with margins straight, or curved; rectangular, or wedge-shaped, or oblong; oblong, or circular; not in groove of raphe; adjacent to hilum; 1–7 mm from hilum; mounded; similar color as testa, or dissimilar color from testa; lighter than testa, or darker than testa; tan; not within corona, halo, or rim. Endosperm present; thick; 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; entire over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; yellow, or tan; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear, or bulbose; lobe tip straight, or curved, or hooked; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons, or 1/2 to nearly length of cotyledons. Plumule rudimentary, or moderately developed; glabrous.
Polhill (1982) monographed the species in Africa and Madagascar, where three-quarters of the species are endemic. To balance his excellent contribution, we also consulted three New World monographs and one from Thailand: North America, Windler (1974a), Colombia, Bernal (1986), Venezuela, Matos (1978), and Thailand, Niyomdham (1978). Miller (1967) studied the seed morphology and anatomy of "40 species probably endemic to the New World, 21 species from the Old World, and four pantropicals." Because of synonomy problems, seeds of only 47 different species are keyed and illustrated. Miller's key seed characters are: Hilum open vs. hilum occluded by radicle, seeds small vs. medium, funicular remnant distinct vs. absent, and glossy vs. not glossy. His term boss is synonymous with our term lens. Windler (1973) noted that like other legume genera, Crotalaria pods have an active ballistic dehiscence. The two valves separate along the "center part of the adaxial suture," and an "explosive inward and upward movement of the lower suture causes the dispersal of the seeds. The valves continue to curl in the same direction, frequently trapping a few seeds in each of the curled valves." Windler reported that in the laboratory seeds were thrown up to five meters. He also noted that movement by water and animals accounted for most seed dispersal. Niyomdham (1978) observed that species of Crotalaria can be divided into two seed groups: Reniform group and cordate (with unequal lobes) or mitiform group. The seeds of Crotalaria exhibit an impressive array of monochrome colors, including, but not limited to, brown (light to dark and in combination with red, gray, yellow, orange, or orange-red), tan, black, orange, red, and yellow. Mottled seeds also occur.
Tribe Crotalarieae
Polhill (1981q) broadly defined tribe Crotalarieae with two generic groups. The first group, without a two-lipped calyx, formed a tight cluster around Lebeckia (3.27.10) in southern Africa. The second group, with a two-lipped calyx, had more scattered distributions and uncertain affinities. Van Wyk (1991) followed Polhill (1981q), and transferred Argyrolobium (3.30.03) from Genisteae (3.30) to the second group. Crotalarieae and related tribes are rich in alkaloids which have been extensively studied in the last decade (Hussain et al. 1988; Van Wyk and Verdoorn, 1989a, 1989b, 1989c, 1990, 1991a, 1991b; Van Wyk et al., 1989, 1993; Verdoorn and Van Wyk, 1990, 1991). Polhill (1994a, 1994b) and Van Wyk and Schutte (1995a), using chemical and morphological data, restricted Crotalarieae to the genera without a two-lipped calyx, and transferred those with a two-lipped calyx to Genisteae, Anarthrophyllum (3.30.06), Argyrolobium (3.30.03), Dichilus (3.30.02), Melolobium (3.30.01), and Sellocharis (3.30.07), except Lebeckia. They also more or less inverted the generic order within the first group according to Van Wyk and Schutte's cladistic analysis for the genera of Crotalarieae, in the narrow sense.
Authors: J.H. Kirkbride, Jr., C.R. Gunn, A.L. Weitzman, M.J. Dallwitz, K.R. Thiele
Content last updated April 2003
Released April 2024 on idtools.org
