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.

TRIFOLIUM

CLOVER

Duane Isely

Annual or perennial herb, unarmed
Leaves generally palmately compound; stipules conspicuous, partly fused to petiole; leaflets generally 3, sometimes 5–9, ± serrate or dentate
Inflorescence: raceme (often umbel-like), head, or spike, axillary or terminal, generally many-flowered, often involucred, generally peduncled; flowers bracted or not
Flower generally spreading to erect, often becoming reflexed; corolla generally purple to pale lavender, sometimes yellow, persistent after flower; 9 filaments fused, 1 free
Fruit generally indehiscent, but often breaking, short, plump, generally included in corolla; base often stalk-like
Seeds 1–6
Etymology: (Latin: 3 leaves)
Reference: [Gillett 1980 Can J Bot 58:1425–1558; Zohary & Heller 1984 Genus Trifolium]

Native

T. albopurpureum Torr. & A. Gray

Annual, hairy
Stem decumbent to erect
Leaves cauline; stipules small; leaflets 1–3 cm, oblanceolate to obovate
Inflorescence: spike, 5–20 mm wide, ovoid to short-cylindric
Flower: calyx 4–15 mm, lobes > or >> tube, tapered or bristle-like, plumose; corolla < or > calyx, 2-colored (purple and white)
Seeds 1–2
Chromosomes: 2n=16,32
Ecology: Coastal dunes, grasslands, wet meadows, open slopes, oak chaparral, pine woodlands, roadsides, other disturbed places
Elevation: < 2100 m.
Bioregional distribution: California Floristic Province
Distribution outside California: to British Columbia, Baja California
Formidable complex here ± arbitrarily divided into 3 intergrading vars.; probably should including T. amoenum.

Native

var. albopurpureum

Flower: calyx 4–8 mm, lobes 3–6.5 mm; corolla 5–8 mm, ± = calyx. Abundant
Ecology: Grassland, oak chaparral, pine forests, roadsides
Elevation: generally < 1100 m (< 2100 m in s).
Bioregional distribution: California Floristic Province
Distribution outside California: to British Columbia, Baja California