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.

ASTRAGALUS

Richard Spellenberg

Annual or perennial herb from crown, glabrous to hairy; hairs sometimes forked at base, branches parallel with leaf surface, sometimes very unequal
Stem 0 or prostrate to erect
Leaves odd-1-pinnate; leaflets generally jointed to midrib; stipules membranous, sometimes fused around stem at stem base
Inflorescence: raceme, axillary, sometimes head- or umbel-like; flowers 2–many
Flower bilateral; calyx 5-lobed; banner outside wings in bud, keel blades with small protrusion at base locking into pit on adjacent wing; 9 filaments fused, 1 free; ovary (and fruit) generally sessile, style slender, stigma minute
Fruit generally 1- or ± 2-chambered, often mottled, generally becoming ± dry; placenta on upper suture
Seeds 2–many, smooth, compressed, ± notched at attachment scar
Species in genus: > 2000 species: ± worldwide (380 in North America, 94 in CA including many rare taxa)
Etymology: (Greek: ankle-bone or dice, perhaps from rattling of seeds within fruit)
Reference: [Barneby 1964 Mem NY Bot Gard 20:1–1188; Isely 1986 Iowa State J Res 61:157–289]
Very difficult; both flower and fruit needed for identification; many good species appear similar; some species complexes need study. Taxa near province boundaries may appear in > 1 key. Varieties keyed under species for simplicity; species with vars. so identified in key. Fr length includes beak and any stalk-like base unless fruit body specified.

Native

A. kentrophyta A. Gray

Perennial, tufted or matted, generally spiny, strigose; hairs attached by base or on side
Stem < 3 dm
Leaf 2–26 mm; stipules sometimes like leaflets, generally minutely spine-tipped, at least lower fused around stem into sheath; leaflets 3–9, 1–17 mm, linear or narrowly lanceolate, ± spine-tipped
Inflorescence: flowers 1–3
Flower: petals white to pink-purple, banner 3.9–9.2 mm, recurved ± 45°, keel 2.9–6.3 mm
Fruit 4–9 mm, 1.5–4 mm wide, compressed side-to-side, finely hairy; sutures prominent; chamber 1
Ecology: Open areas, clay, gravel, talus, rock
Elevation: 2280–3660 m.
Bioregional distribution: c&s High Sierra Nevada, East of Sierra Nevada
Distribution outside California: to s Canada, ND, Colorado, New Mexico

Native

var. danaus (Barneby) Barneby

SWEETWATER MOUNTAINS MILKVETCH

Plant a dense, rounded, very spiny cushion, strigose; hairs simple
Stem generally < 5 cm
Leaf 4–20 mm; leaflets 3 (sometimes 5 on lower leaves), 3–7 mm, stiff, spine-tipped
Flower: petals pale purple or whitish with purple keel-tip, banner 4–5.6 mm, keel 3.3–4.1 mm
Fruit: immature seeds 5–8
Ecology: UNCOMMON. Rocky places at and above timberline
Elevation: 3000–3600 m.
Bioregional distribution: c&s High Sierra Nevada, East of Sierra Nevada
Flowering time: Jul–Sep