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.

LATHYRUS

WILD PEA

Duane Isely

Annual or perennial herb, unarmed, glabrous or hairy, rarely glandular, generally rhizomed
Stem sprawling, climbing, or erect; stem angled, flanged, or winged
Leaves even-1-pinnate; stipules persistent, upper lobe > lower; main axis ending as a tendril or short bristle; leaflets 0–16, ± opposite or alternate, linear to widely ovate
Inflorescence: raceme, generally axillary, 1–many-flowered
Flower: upper calyx lobes generally < and wider than lower; corolla 8–30 mm, pink-purple or pale, sometimes white or yellow; 9 filaments fused, 1 free; style flat, finely hairy on concave side
Fruit dehiscent, oblong, ± flat
Species in genus: ± 150 species: temp North America, Eurasia
Etymology: (Ancient Greek name)
Reference: [Broich 1987 Syst Bot 12:139–153]
Some species variable, intergrading with others; some hybridization probable. Seeds of most alien species. TOXIC to humans (especially young males) and livestock (especially horses).

Native

L. jepsonii Greene

Perennial, glabrous to puberulent
Stem climbing, winged
Leaf: stipules small, generally narrow; leaflets 10–16, generally subopposite to alternate, 3.5–5.5 cm, lanceolate or oblong-lanceolate; tendril branched, coiled
Inflorescence 6–15-flowered
Flower: calyx tube > upper lobes, ± = lower; corolla 15–20 mm, generally pink to pink-purple
Fruit glabrous
Chromosomes: 2n=14
Ecology: Forests, open areas, coastal and estuarine marshes
Elevation: < 1500 m.
Bioregional distribution: Klamath Ranges, North Coast Ranges, Cascade Range, n Sierra Nevada, Great Central Valley, Central Western California.

Native

var. jepsonii

DELTA TULE PEA

Plant glabrous, often robust (stem < 2.5 m)
Ecology: Coastal and estuarine marshes
Elevation: < 30 m.
Bioregional distribution: Great Central Valley, especially San Francisco Bay Area.