Lens

Taxonomy

Lens P. Miller Nom. cons. Gard. Dict. Abr. ed. 4. 28 Jan 1754.

Subfamily: Faboideae.
Phylogenetic Number: 3.19.03.
Tribe: Fabeae.
Species Studied - Species in Genus: 2 studied; 4 in genus.

Description

Fruit: A legume; unilocular; 0.9–1.6 cm long; 0.4–1.2 cm wide; 0.15–0.2 cm thick; length less than twice as long as width, or 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; not plicate; not twisted; asymmetrical; oblong; with both sutures nearly straight; not inflated; compressed; without beak; short tapered at apex; aligned with longitudinal axis of fruit; short tapered at base; oblique with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous; seed chambers externally visible, or invisible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active, or passive; with valves enrolling, or twisting. Replum invisible. Epicarp dull; monochrome; reddish brown, or tan; with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent; with pubescence gray; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; 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; chartaceous. Endocarp present; visible; dull; opaque; monochrome; tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) (1–)2; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 1 mm long; of 1 length only; filiform; straight. Aril absent (funiculus dilated).

Seed: 3–8 mm long; 3–8 mm wide; 1.5–3 mm thick; not overgrown; not angular; symmetrical; circular; compressed; without visible 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; colored; monochrome, or mottled and streaked (mainly streaks); with frequent mottles; with frequent streaks; reddish brown, or tan (cream); with black overlay; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; with faboid split; with the lips of the faboid split lighter colored than the rest of the hilum and therefore conspicuous; larger than punctiform; 1–1.5 mm long; with straight outline; linear; marginal according to radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.3–0.7 mm long; with margins straight, or curved; linear; circular; not in groove of raphe; adjacent to hilum; 0.5–1.2 mm from hilum; mounded; dissimilar color from testa; darker than testa; black; not within corona, halo, or rim. Endosperm present; trace; not pluglike and not resembling tip of radicle; restricted to region of embryo (around radicle area); 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; split over radicle; with lobes; with lobes not touching; with the interface division terminating at base of radicle; without margins recessed; white, or yellow, or orange; 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; deflexed and parallel to cotyledon length (more or less); centered between cotyledons; less than 1/2 length of cotyledons. Plumule well developed; glabrous.

Distribution

Mediterranean region, West and Central Asia, Ethiopia, and Zaire, and now widely cultivated.

Old World; Europe to Mediterranean to Russia to Southwest Asia to Africa to Macaronesia (to Uganda, Ethiopia, and Zaire).

Worldwide crop.

Generic Notes

The number of species in this genus has been open to question for many years. Most authors recognized the cultivated and commercially important lentil, L. culinaris F.C. Medikus. In the past, at least three wild species have been recognized. Ladizinsky et al. (1984), using extensive crossability and cytological studies, recognized one additional species, L. nigricans (F.A. Marchall von Bieberstein) D.A. Godman. The two other often recognized species of Lens, L. ervoides and L. orientalis (P.E. Boissier) H. Handel-Mazzetti, are now L. nigricans subsp. ervoides (L. grande) G. Ladizinsky and L. culinaris subsp. orientalis (P.E. Boissier) J. Ponert. The fifth species, L. montbretii (F.E.L. von Fischer & C.A.A. von Meyer) P.H. Davis & U. Plitmann, had been assigned to Lens (Barulina, 1930, Davis and Plitmann, 1970), but Ladizinsky and Sakar (1982) provided morphological and karyological data suggesting that this species be returned to Vicia (19.01) where it was originally placed as V. montbretii (Hoffman et al., 1986). Ladizinsky (1997) described a new species of Lens from southeastern Turkey, L. tomentosus G. Ladizinsky, utilizing evidence from morphology, crossing, and cpDNA. Ferguson et al. (2000) reassessed the genus, and concluded that there are only four species in the genus: L. culinaris, L. ervoides, L. nigricans, and L. lamottei Z.V. Czefranova and that L. culinaris has four subspecies: subsp. culinaris, subsp. orientalis, subsp. tomentosus (G. Ladizinsky) M.E. Ferguson, N. Maxted, M.W. van Slagren & L.D. Robertson, and subsp. odemensis (G. Ladizinsky) M.E. Ferguson, N. Maxted, M.W. van Slagren & L.D. Robertson. Our species count of four follows Ferguson et al. (2000). The history of L. culinaris extends as far back as agriculture itself. Like Pisum (19.04), Lens has been closely associated with cultivation of grains in the Near East (Zohary and Hopf, 1973).

Tribal Notes

Tribe Fabeae

This tribe has traditionally been called Vicieae. Article 19.4 of the International Code of Botanical Nomenclature (Greuter et al., 1994) stated, "The name of any subdivision of a family that includes the type of the adopted, legitimate name of the family to which it is assigned is to be based on the generic name equivalent to the type." Faba P. Miller is the type of Fabaceae, and is synonymous with Vicia. Therefore because Faba is included in this tribe, the tribe must be called Fabeae. Endo and Ohashi (1997) have proposed, after a cladistic analysis using morphological characters, including internal seed morphology, that Cicereae (20) and Fabeae (Vicieae) formed a monophyetic group whose sister group is Trifolieae (21). Butler (2002) examined the exterior micromorpholgical characters of Fabeae fruits. She concluded that the genera are so variable that they can not be identified using these characters and that wild forms also can not be separated domesticated forms using exterior micromorpholgical characters. Therefore, domestication has not affected the exterior micromorpholgical characters of Fabeae fruits.