Trigonella

Taxonomy

Trigonella C. Linnaeus Sp. Pl. 776. 1 Mai 1753.

Subfamily: Faboideae.
Phylogenetic Number: 3.21.04.
Tribe: Trifolieae.
Species Studied - Species in Genus: 25 studied; ca. 61 in genus.

Description

Fruit: A legume; unilocular; 1–11 cm long; 0.09–1.3 cm wide; 0.07–0.08 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx, or deciduous calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight to curved (slightly), or 0.5-coiled, or contorted; loosely plicate; not twisted; asymmetrical, or symmetrical; linear, or ovate, or circular, or moniliform, or C-shaped, or falcate; with 1 straight and 1 curved suture, or both sutures parallelly curved; widest near middle or D-shaped; inflated, or not inflated; compressed, or flattened, or terete; without beak, or with beak; straight, or declined; with solid beak the same color and texture as fruit; long tapered at apex, or rounded at apex; aligned with longitudinal axis of fruit; tapered at base, or short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous, or coriaceous; seed chambers externally visible; seed chambers with the raised seed chambers not torulose, or torulose; margin not constricted, or constricted; margin slightly constricted along both margins, or constricted only on 1 margin; margin without sulcus; margin plain, or embellished; margin with prickles, or wing(s); wing(s) absent, or present (rarely); wing(s) 1; wing(s) 1–2 mm wide; wing(s) sutural; wing(s) on both sutures, or 1 suture; nonstipitate, or substipitate; indehiscent (gaping or not along seed-bearing suture), or with all layers dehiscing (rarely); splitting along suture(s). Dehiscence of valves along both sutures, or 1 suture; apical and down; passive. Replum invisible. Epicarp dull; monochrome; tan (to white); with surface texture uniform; glabrous, or pubescent and indurate; with hairs appressed, or erect; with 1 type of pubescence; puberulent; with pubescence gray; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; veined; reticulately veined, or longitudinally veined relative to fruit length (and veins twisted); not tuberculate; warty; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present, or absent; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; remaining fused to epicarp; without wings, or with wing(s) extending into epicarp (rarely); entire. Seed(s) 1–20; length parallel with fruit length, or transverse to fruit length; neither overlapping nor touching, or touching; in 1 series. Funiculus 0.1–0.6 mm long; of 1 length only; filiform; curved. Aril absent.

Seed: 1.5–5 mm long; 0.5–3 mm wide; 0.5–1.6 mm thick; not overgrown; angular, or not angular; asymmetrical; mitaform, or oblong, or ovate, or quadrangular, or rectangular, or rhombic, or elliptic, or linear, or circular (sub); compressed; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; 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, or mottled and streaked; with frequent mottles, or infrequent mottles; with frequent streaks, or infrequent streaks; yellowish, greenish, or dark brown, or yellow (or pale), or orange, or green (grayish); with black overlay, or brown overlay; glabrous; not smooth, or smooth; with elevated features; tuberculate, or wrinkled, or verrucose; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or partially concealed; concealed by funicular remnant, 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; not within corona, halo, or rim. Lens not discernible, or discernible; with margins straight, or curved; triangular, or irregular; circular, or irregular; not in groove of raphe; adjacent to hilum; 0.1–0.3 mm from hilum; mounded; similar color as testa; darker than testa; reddish brown; not within corona, halo, or rim. Endosperm present; thin, or 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; 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 moderately developed; glabrous.

Distribution

Central Europe to South Africa to Canary Islands and Central Asia, And Australia (1 sp.).

Old World; Europe to Mediterranean to Russia to Africa to Southwest Asia to India to China to Mongolia to Australia (1 sp., Trigonella suavissima J. Lindley, in Australia; Africa (South); Asia (central)).

New World crop (T. foenum–graecum).

Generic Notes

There is a rich history of authors trying to separate Trigonella and Medicago (21.05), and most of this history was summarized by Baum (1968). The recent publications of Small (1986, 1987a, 1987b) have clarified this separation. Small and Jomphe (1989a) transferred some species of Trigonella to Medicago, and our species count reflects these and other transfers. Our species count is based on Small (1989), and not on Heyn (1981), who had ca. 80. Small (pers. comm., 1997) noted that the number of perennial Asian species can only be roughly estimated.

Tribal Notes

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.