Subfamily: Faboideae.
Phylogenetic Number: 3.21.01.
Tribe: Trifolieae.
Species Studied - Species in Genus: 27 studied; ca. 75 in genus.
Fruit: A legume; unilocular; 0.8–1.6 cm long; 0.2–0.4 cm wide; 0.02–0.04 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx, or deciduous calyx; with calyx longer than fruit, or equal in length to fruit, or shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical, or symmetrical; linear, or oblong, or rhombic, or ovate (rarely); with 1 straight and 1 curved suture; widest near middle or D-shaped; not inflated; compressed; without beak; short tapered at apex; aligned with longitudinal axis of fruit; short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally invisible; margin constricted, or not constricted; margin slightly constricted along both margins; margin without sulcus; margin plain; wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves twisting. Replum invisible. Epicarp dull; monochrome; tan; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; pilose, or puberulent; with pubescence golden, or gray; with pubescence uniformly distributed; with glandular hairs and simple hairs; pliable; with hair bases plain, or swollen; glandular; with glandular hairs; without spines; not smooth; with elevated features; not veined; not tuberculate; tuberculate (bases of hairs); 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. Endocarp present; visible; dull, or glossy; opaque; monochrome; tan; smooth; without adhering pieces of testa; septate, or nonseptate; with septa thicker than paper, firm; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 5–10; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.5–1 mm long; of 1 length only; thick; straight. Aril absent.
Seed: 0.5–5.5 mm long; 0.5–5 mm wide; 1–4.5 mm thick; not overgrown; not angular, or angular; asymmetrical; mitaform, or ovate, or reniform, or C-shaped (with cotyledon and radicles more or less of equivalent size and on each side of a deep hilar sinus), or triangular; compressed, or terete; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; with deep 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; dull; not modified by a bloom; colored; monochrome (occasionally with white tubercles); dark to light reddish brown, or tan, or yellow; glabrous; not smooth, or smooth; with elevated features, or recessed features; tuberculate (some quite prominent in size and or color), or rugose (rarely); punctate; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe visible; from hilum to lens; not bifurcating; darker than testa; tan; flush. Hilum present; visible, or fully concealed, or partially concealed; concealed by funiculus, or wing; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform; between cotyledon and radicle lobe; recessed; within rim; rim color of testa. Lens discernible; 0.5–1 mm long; with margins straight, or curved; oblong, or linear; circular, or elliptic, or oblong; not in groove of raphe; adjacent to hilum; 0.1–0.2 mm from hilum; mounded; similar color as testa; darker than testa; reddish brown, or tan (reddish), or black (ish); not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa, or embryo. 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; inner face flat; glabrous on inner face. Embryonic axis straight; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear; lobe tip straight, or curved, or hooked; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary, or moderately developed; glabrous.
FÖrther and Podlech (1991) revised the polymorphic O. natrix C. Linnaeus group of seven species. La Sota (1978) studied the testa morphology of ten Ononis species.
Tribe Trifolieae
Endo and Ohashi (1997) have proposed, after a cladistic analysis using morphological characters, including internal seed morphology, that Cicereae (20) and Fabeae (19) formed a monophyetic group whose sister group is Trifolieae. Ononis and Parochetus (21.02) "are not nearly as closely related to the remaining four genera as the latter are to each other, and indeed that the two genera are not at all closely related to each other (or so far as I know to anything else)" (E. Small, pers. comm. 1997). Butler (1996) presented a table with eight seed characteristics of 14 Medicago (21.05) spp., seven Melilotus (21.03) spp., 25 Trifolium (21.06) spp., 11 Trigonella (21.04) spp., and two Ononis spp. as an aid for their identification in archaeological sites.
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
