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.

PROSOPIS

MESQUITE

Elizabeth McClintock

Shrub, tree; stipular spines generally 2 per node; roots long, spreading
Leaves even-2-pinnate, alternate, deciduous; 1° leaflets generally 1–2 pairs, opposite; 2° leaflets generally many, opposite
Inflorescence: raceme, axillary, spike-like or spheric head, many-flowered
Flower radial, small, greenish white or yellow; calyx shallowly bell-shaped, lobes very short; petals generally inconspicuous; stamens 10, exserted, free; style exserted, generally appearing before stamens
Fruit indehiscent, ± flat, ± narrowed between seeds or tightly coiled, pulpy when young, then woody
Seeds several
Species in genus: ± 44 species: especially Am (also sw Asia, Africa)
Etymology: (Greek: burdock, for obscure reasons)
Reference: [Burkhart 1976 J Arnold Arbor 57:220–524; Holland 1987 Madroño 34:324–333]
Used for timber, firewood, shade, ornamental, bee, human, and livestock food.

Native

P. glandulosa Torr. var. torreyana (L.D. Benson) M.C. Johnst.

MESQUITE, HONEY MESQUITE

Shrub, tree < 7 m, ± glabrous; crown often wider than tall
Stem: branches arched, crooked; spines 0.5–4 cm
Leaf glabrous; 1° leaflets generally 1 pair, 6–17 cm; 2° leaflets 7–17 pairs, 1–2.5 cm, oblong, length 7–9 X width
Inflorescence: raceme, 6–10 cm, spike-like
Flower: petals free, 2.5–3.5 mm
Fruit 5–20 cm, slightly narrowed between seeds, glabrous
Seeds generally 5–18, 6–7 mm, oblong
Ecology: Common. Grasslands, alkali flats, washes, bottomlands, sandy alluvial flats, mesas
Elevation: 0–1700 m.
Bioregional distribution: San Joaquin Valley, Peninsular Ranges, Desert
Distribution outside California: to Texas, Mexico
Flowering time: Apr–Aug
Horticultural information: SUN, DRN: 7, 9, 10, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 &IRR: 8, 11, 13; also STBL.