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.

MELILOTUS

SWEETCLOVER

Duane Isely

Annual or biennial, unarmed
Stem generally erect
Leaves odd-1-pinnate; stipules generally narrow or bristle-like, bases fused to petiole; leaflets 3, margin toothed or wavy
Inflorescence: raceme, axillary or terminal, slender or short-cylindric, many-flowered
Flower: calyx lobes ± equal; corolla yellow or white; 9 filaments fused, 1 free
Fruit indehiscent, 2–4 mm, ovoid, compressed but thick, leathery, ridged or bumpy
Seeds 1–2
Species in genus: 20 species: Eurasia, especially Medit; several species widely cultivated for soil improvement and naturalized
Etymology: (Greek: honey-Lotus)
Reference: [Isely 1954 Proc Iowa Acad Sci 61:119–131]
TOXIC: inclusion in hay enhances production of mold toxins that may cause cattle death from hemorrhaging.