Perennial herbs, erect, ± pilosulous. Stems 1.5–4 dm, black-warty. Principal leaves 3–8(–9.5) cm; leaflets (5 or) 7 or 9 (or 11), blades obovate, (5–)7–17 mm, margins entire or ± crenulate, surfaces glandular-pustulate around margins abaxially. Peduncles 1–8(–11) cm. Inflorescences racemes, spikelike, relatively densely flowered, not involucrate, (15–)16–19(–20) mm diam.; axis usually not visible, 2.5–5 cm; bracts deciduous, 7–11 mm. Calyces ± symmetric, (4.3–)5.8–7.7 mm, pilose; tube 2.6–3.1 mm, with 3 or 4 small glands between ribs, lobes triangular-aristate. Corollas dark blue or blue-violet; papilionaceous; banner 5.7–7.6 mm, blade shallowly cordate, (3.5–)3.8–4.8 × 2.2–3.8 mm; epistemonous petals attached well proximal to middle of stamen tube; wings 3.7–5 × 1.3–1.8 mm; keel connate by overlapping margins, blades (3.8–)4–4.7 × 1.7–2.2 mm. Stamens 10, 6.6–8.7 mm, filaments distinct to 2.3–2.9 mm, anthers (0.5–)0.6–0.8 mm. Legumes (3–)3.3–4 mm, pilosulous distally, eglandular. Seeds 1.8–2.4 mm. 2n = 14.
Phenology: Flowering late summer–fall.
Habitat: Open deserts, dry grasslands, open woodlands, sometimes on limestone.
Elevation: 1000–1800 m.
Distribution
Ariz., N.Mex., Tex., Mexico (Chihuahua, Coahuila, Sonora).
Discussion
Dalea lachnostachys occurs in southern Arizona, southwestern New Mexico, and trans-Pecos Texas.
Selected References
None.