Lathyrus

Taxonomy

Lathyrus C. Linnaeus Nom. cons. prop. Sp. Pl. 729. 1 Mai 1753.

Subfamily: Faboideae.
Phylogenetic Number: 3.19.02.
Tribe: Fabeae.
Species Studied - Species in Genus: 75 studied; 161 in genus.

Description

Fruit: A legume; unilocular; 2.5–10 cm long; 0.2–1 cm wide; 0.15–0.4 cm thick; 2–9 times longer than wide, or more than 9 times longer than wide, or length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight, or curved (slightly); not plicate; not twisted; asymmetrical, or symmetrical; linear to rhombic (linear); with both sutures nearly straight; not inflated; flattened, or compressed; without beak; short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; long tapered at base, or short tapered at base; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous, or membranous, or chartaceous, or ligneous (L. lentiformis U. Plitman); seed chambers externally visible (faintly to visible), or invisible; seed chambers with the raised seed chambers not torulose, or torulose; margin not constricted; margin without sulcus; margin plain, or embellished; margin with wing(s); wing(s) absent, or present; wing(s) sutural, or valvular (occasionally); wing(s) on both valves; wing(s) on both sutures; nonstipitate, or stipitate (infrequent, see L. setifolius C. von Linneaus); with all layers dehiscing, or indehiscent (L. lentiformis); splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves twisting. Replum invisible. Epicarp dull; monochrome; reddish brown, or tan; with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect, or appressed; with 1 type of pubescence; pilose; with pubescence gray; with simple hairs; pliable; with hair bases swollen, or plain; glandular; with glandular hairs (L. cassius P.E. Boissier); without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; papillose (L. hirsutus C. Linnaeus), or glandular dotted (section Orobus (C. Linnaeus) J.G. Baker); 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, or chartaceous. Endocarp present; visible; dull; opaque; monochrome; tan; smooth; without adhering pieces of testa; nonseptate, or septate; with septa thin (tissue paper-like), flexible; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings, or with wing(s) extending into epicarp; entire. Seed(s) 1–25; length parallel with fruit length, or transverse to fruit length; touching; in 1 series. Funiculus of 1 length only; thick; straight. Aril absent (funiculus may be expanded and remain over hilum and is not an aril).

Seed: 1.5–10 mm long; 1.5–10 mm wide; 1.3–7 mm thick; not overgrown; not angular, or angular; symmetrical, or asymmetrical (with or without dents because of adjacent seed pressures); oblong, or circular (to subcircular), or rectangular, or quadrangular, or triangular (compressed), or irregular (angular); terete, or compressed (rarely); 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, or glossy; not modified by a bloom, or modified by a bloom; colored; monochrome, or mottled; with frequent mottles; brown (diverse shades and in combinations with other colors), or black (with or without purplish tinge), or tan; with brown overlay (blackish); glabrous; smooth, or not smooth; with elevated features; tuberculate (either aligned or not in rows or united into short ridges or not), or wrinkled (faintly); coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible, or visible; from hilum through lens and base of seed to point opposite hilum; not bifurcating; darker than testa; black (color of mottles). Hilum present; visible, or partially concealed, or fully concealed; concealed by funiculus, or funicular remnant; with faboid split; with the lips of the faboid split lighter colored than the rest of the hilum and therefore conspicuous; larger than punctiform; 0.3–5 mm long; with curved outline, or angular outline, or straight outline; circular, or elliptic; wedge-shaped; oblong, or linear; subapical to radicle tip, or marginal according to radicle tip; flush, or recessed; not within corona, halo, or rim (though some species with light colored seeds with mottles concentrated around hilum somewhat like a necklace). Lens discernible; 0.1–1.5 mm long; with margins straight, or curved; oblong, or linear, or triangular, or rhombic; circular, or oblong; not in groove of raphe; adjacent to hilum, or confluent with hilum; touching to 1 mm from hilum; mounded, or recessed; dissimilar color from testa; darker than testa; reddish brown, or black, or red; not within corona, halo, or rim. Endosperm absent, or present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa (but enclosing radicle). Cotyledons not smooth; both outer faces convex; both the same thickness, or one thicker than the other; 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; 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; deflexed and parallel to cotyledon width; centered between cotyledons; less than 1/2 length of cotyledons. Plumule well developed; glabrous.

Distribution

North and South America, Europe, North, East, and tropical Africa, and Asia.
New World, or Old World; Alaska to Canada to United States, or Mexico, or South America (to temperate); Argentina, Peru, Brazil, and the Guianas; Europe to Mediterranean to Russia to Africa to Southwest Asia to India to Indochina to China to Korea to Japan to Mongolia to Macaronesia (Africa (to tropical East)).

Worldwide crop (ornamental).

Generic Notes

Kupicha (1983) classified the Old World and New World species and recognized 13 sections. Asmussen and Liston (1998) conducted cladistic analyses of 42 Lathyrus species from 12 of Kupicha's sections using chloroplast DNA. Their results indicated that Lathyrus should to be organized in 6–8 sections, not 13. Hitchcock (1952) monographed the North American species. Bässler (1966, 1973, 1981) studied some of the Old World species, and Hung-pin (1984) extended his studies to China. Butler (1986) investigated the testa of Lathyrus using the scanning electron microscope, and her results are published in the Kaul and Combes (1986) book "Lathyrus and Lathyrism." Lathyrism is an animal expression of the toxic components of Lathyrus species, especially L. sativus. Several species produce aerial and subterranean fruits, e.g., L. amphicarpos C. Linnaeus and L. ciliolatus K. H. Rechinger. Kupicha discussed the fruits of Lathyrus and illustrated their external variations in a full-page plate. The drawing of L. lentiformis fruit is especially interesting (figure 5, k). Kupicha also recorded the relative hilum lengths for the 13 sections. The number of species is from Asmussen and Liston (1998).

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.