Phaseolus

Taxonomy

Phaseolus C. Linnaeus Sp. Pl. 723. 1 Mai 1753.

Subfamily: Faboideae.
Phylogenetic Number: 3.10.72.
Tribe: Phaseoleae.
Subtribe: Phaseolinae.
Species Studied - Species in Genus: 34 studied; 36 in genus.

Description

Fruit: A legume; unilocular; 1–18 cm long; 0.2–2 cm wide; 0.2–1.1 cm thick; length less than twice as long as width, or 2–9 times longer than wide, or more than 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, or curved (or slightly curved); not plicate; not twisted; asymmetrical, or symmetrical; linear, or falcate, or irregular; with both sutures parallelly curved, or both sutures unequally curved, or 1 straight and 1 curved suture; widest near middle or D-shaped; not inflated; flattened to compressed to terete; without beak, or with beak; declined, or hooked; with solid beak the same color and texture as fruit; long tapered at apex to tapered at apex to short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; 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 to chartaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain, or embellished; margin with thickened sutural areas; 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, or multicolored; mottled; yellow to tan to brown to black, or green, or red; with brown overlay; mottling color combination constant; with mottling over seed chambers; with surface texture uniform; glabrous, or glabrate, or pubescent and indurate; with hairs erect; with 1 type of pubescence, or 2 types of pubescence; puberulent, or pilose, or strigose, or pilose and puberulent; with pubescence golden, or white; with pubescence uniformly distributed; with simple hairs; pliable, or pliable and stiff; with hair bases plain, or swollen; glandular, or eglandular; with glandular dots; without spines; smooth, or not smooth; with elevated features; not veined; not tuberculate; dotted, or wrinkled, or wrinkled and dotted; 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 reniform canals; solid; coriaceous to chartaceous. Endocarp present; visible; dull; opaque; monochrome; tan, or white; smooth; without adhering pieces of testa; septate, or subseptate; with septa thin (tissue paper-like), flexible; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; remaining fused to epicarp; without wings; entire. Seed(s) 1–12(–20); length parallel with fruit length, or transverse to fruit length (rarely); neither overlapping nor touching; in 1 series. Funiculus 0.5–1 mm long; of 1 length only; flattened; straight, or triangular. Aril present, or absent; dry; when dry tongue-aril; fimbriate; cream.

Seed: 1.5–33 mm long; 1.5–20 mm wide; 1–12 mm thick; not overgrown; not angular, or angular; symmetrical, or asymmetrical; elliptic, or reniform, or trapezoid, or irregular, or oblong, or ovate; compressed, or flattened, or terete, or quadrangular; with surface smooth; without visible radicle and cotyledon lobes; with shallow 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; glossy to dull; not modified by a bloom; colored, or clear; monochrome, or mottled, or bichrome; with frequent mottles; greenish brown or reddish brown to brown, or black, or white, or red, or brown and white; with brown overlay, or brown overlay and tan overlay, or black overlay; glabrous; smooth, or not smooth; with elevated features; rugose, or wrinkled; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe visible, or not visible; from hilum to near base of seed and terminating, or hilum through base of seed and up the other side; not bifurcating; color of testa; raised, or recessed. Hilum present; fully concealed; concealed by funicular remnant; with faboid split; larger than punctiform; 0.3–6 mm long; with curved outline; narrowly elliptic to circular, or oval (narrowly); apical according to radicle tip but marginal according to seed length; recessed, or flush, or raised; within rim; rim color of testa, or darker than testa. Lens discernible; 0.5–2 mm long; with margins straight, or curved; triangular; circular; not in groove of raphe; confluent with hilum; mounded; same color as testa, or similar color as testa; lighter than testa, or darker than testa; black, or brown, or tan; within rim, or not within corona, halo, or rim; rim color of testa. Endosperm absent. 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, or not entire 180 degrees from base of radicle; wavy; similar at apex; partially concealing radicle; notched at radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed, or with margin(s) recessed; with 1 margin recessed; recessed on same side as radicle; white, or yellow, or tan; inner face slightly concave, or flat; glabrous on inner face. Embryonic axis oblique, or parallel, or right angled; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; slightly bulbose, or linear; lobe tip slightly curved, or straight; oblique to cotyledons; centered between cotyledons; less than 1/2 length of cotyledons. Plumule moderately developed to well developed; glabrous.

Distribution

New World, And widely cultivated.

New World; United States, Mexico, West Indies, Central America, and South America (Central America: Guatemala, Honduras, Nicaragua, El Salvador, Costa Rica, and Panama; South America: Ecuador, Peru, Bolivia, and Argentina); Argentina, Peru, and the Guianas.

Worldwide crop.

Generic Notes

Delgado Salinas (1985) monographed North and Central American Phaseolus, and his species count is used, not Lackey (1981). Delgado Salinas et al. (1988) described and illustrated (Fig. 7) the dehiscence slit found in P. vulgaris C. Linnaeus and P. leptostachyus G. Bentham. The dehiscence slit is a short opening in the fruit suture close to the pedicel prior to full dehiscence. Seeds can not pass through it, but females of Zabrotes subfasciatus, a bruchid, pass through the slit to oviposit on the first seed. Females of Acanthoscelides obtectus and A. obvetalus, also bruchids, oviposit directly through the dehiscence slit. Four species of large-seeded Phaseolus are commonly cultivated as human food (Duke, 1981; Schery, 1972): P. acutifolius, tepary bean; P. coccineus C. Linnaeus, scarlet runner bean; P. lunatus C. Linnaeus, lima bean; and P. vulgaris, bean or common bean. Phaseolus vulgaris is the most frequently and widely cultivated of the four with its protein content ranging from 17–37 percent and an average of about 25 percent (Duke, 1981; Schery, 1972). The seed coat contains 4.8 percent of the protein in the seed (Werker, 1997).

Tribal Notes

Tribe Phaseoleae

Bruneau et al. (1995) carried out cladistic analyses of tribe Phaseoleae using chloroplast DNA restriction site data. Their results indicated that the tribe is not monophyletic and that the tribal delimitations between Phaseoleae and Desmodieae (11) and between Phaseoleae and Millettieae (7) are problematic.