Pisum

Taxonomy

Pisum C. Linnaeus Sp. Pl. 727. 1 Mai 1753.

Subfamily: Faboideae.
Phylogenetic Number: 3.19.04.
Tribe: Fabeae.
Species Studied - Species in Genus: 2 studied; 2 in genus.

Description

Fruit: A legume; unilocular; 3–12 cm long; 0.8–2.5 cm wide; 0.25–0.5 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with 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; oblong, or linear; with both sutures nearly straight, or both sutures parallelly curved; not inflated, or inflated; terete, or compressed; without beak; short tapered at apex; aligned with longitudinal axis of fruit; long tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally invisible, or visible; seed chambers with the raised seed chambers not torulose; margin not constricted; 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; brown, or yellow, or green; with surface texture uniform; glabrous; 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; coriaceous. Endocarp present; visible; dull; opaque; monochrome; brown; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 5–10 (estimated); length parallel with fruit length; touching; in 1 series. Funiculus of 1 length only; thick; straight. Aril absent (funiculus dilated at apex).

Seed: 3.7–9 mm long; 3.7–9 mm wide; 3.7–7 mm thick; not overgrown; angular, or not angular; symmetrical, or asymmetrical; circular, or irregular (angular); terete; 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; not modified by a bloom, or modified by a bloom; colored; monochrome, or mottled and streaked; with frequent mottles; with frequent streaks; dark or dark reddish brown, or tan (to greenish), or red, or green; with brown overlay (dark reddish); glabrous; smooth, or not smooth; with elevated features; rugose, or tuberculate (minutely), or wrinkled; chartaceous, or 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; with faboid split; with the lips of the faboid split the same color as the rest of the hilum, or lighter colored than the rest of the hilum and therefore conspicuous; larger than punctiform; 1.6–2.1 mm long; with curved outline; elliptic; marginal according to radicle tip; flush; not within corona, halo, or rim. Lens discernible; 1–2 mm long; with margins curved; circular, or elliptic; not in groove of raphe; adjacent to hilum; 1.5–2 mm from hilum; mounded; dissimilar color from testa; darker than testa; black, or brown, or tan; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo (and forming sheath around radicle); 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 the interface division terminating at base of radicle; without margins recessed; white, 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; bulbose; deflexed and parallel to cotyledon length; centered between cotyledons; 1/2 to nearly length of cotyledons. Plumule well developed; glabrous.

Distribution

Mediterranean region and now widely cultivated.

Old World; Europe to Mediterranean to Russia to Southwest Asia to Africa (north).

Worldwide crop.

Generic Notes

The past literature is repleat with numerous scientific names used at various taxonomic levels, Because of the intense breeding of the pea, P. sativum, a major crop. Currently only two species are recognized, and the other species is P. fulvum J. Sibthorp & J.E. Smith. Jha and Ohri (2002) examined the seed proteins of the two Pisum species and concluded that their seed proteins do not distinguish them, however they continued to support two species in the genus because of the reproductive isolation of P. sativum from P. fulvum. Pisum fulvum can have both aerial and subterranean fruits. Pisum sativum was cultivated in "early Neolithic farming villages of the Near East (7,000 to 6,000 B.C.)" (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.