FABACEAE

LEGUME FAMILY

Annual to tree
Leaves generally compound, alternate, stipuled; leaflets generally entire
Inflorescence: generally raceme, spike, umbel or head; flowers sometime 1–2 in axils
Flowers generally bisexual, generally bilateral; hypanthium generally flat or cup-like; sepals generally 5, fused; petals generally 5, free, or the 2 lower ± fused; stamens 1–many, often 10 with 9 filaments at least partly fused, 1 (uppermost) free; pistil 1, ovary superior, generally 1-chambered, ovules 1–many, style, stigma 1
Fruit: legume, sometimes including a stalk-like base above receptacle, dehiscent, or indehiscent and breaking into 1-seeded segments, or indehiscent, 1-seeded, and achene-like
Seeds 1–several, often ± reniform, generally hard, smooth
Genera in family: ± 650 genera, 18,000 species: worldwide; with grasses, requisite in agriculture and most natural ecosystems. Many cultivated, most importantly Arachis , peanut; Glycine , soybean; Phaseolus , beans; Medicago ; Trifolium ; and many orns
Reference: [Polhill & Raven (eds) 1981 Advances in legume systematics; Allen & Allen 1981 Leguminosae]
Family description and key to genera by Duane Isely.

LOTUS

Duane Isely

Annual, perennial herb, shrub, unarmed
Leaves generally odd-1-pinnate (sometimes ± palmately compound, rarely some or most simple); stipules conspicuous or not; leaflets 3–many, often irregularly arranged
Inflorescence: umbel or 1–2-flowered, axillary, generally peduncled, often bracted
Flower: corolla generally yellow (sometimes white or pink), fading darker; 9 filaments fused, 1 free
Fruit dehiscent or not, exserted from calyx or not, ovoid to oblong, ± beaked
Seeds 1–several
Etymology: (Greek: derivation unclear)
Reference: [Isely 1981 Mem New York Bot Garden 25:128–206]
Spp. generally variable; intermediates may be hybrids. Key below separates natural groups.

Native

L. humistratus Greene

Annual, often ± fleshy, hairy
Stem mat-forming to ascending
Leaf subpinnate or palmate; stipules gland-like; leaflets generally 4, ± alternate, 4–12 mm, elliptic or obovate; axis flat, ± blade-like
Inflorescence axillary, 1-flowered, ± sessile
Flower: calyx 3–6 mm, lobes 1–2 X tube; corolla 5–9 mm, yellow, wings ± = keel
Fruit dehiscent, ascending, 6–12 mm, generally 3–4 mm wide, oblong
Seeds few
Chromosomes: 2n=12
Ecology: Abundant. Grassland, oak and pine woodland, desert flats and mtns, roadsides
Elevation: < 1700 m.
Bioregional distribution: California Floristic Province, Desert
Distribution outside California: to sw Utah, w New Mexico, Mexico
Flowering time: Mar–Jun
Horticultural information: DRN, DRY: 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24; STBL.