Shrubs, erect, 0.3–2 m, armed. Stems terete, puberulent or gla­brescent; prickles infra-stipular, usually solitary, rarely groups of 2 or 3, recurved; brachy­blasts present. Leaves: stipules subulate, 1.5–5.5 mm, glabrous; petiole 0.3–1 cm; primary rachis 0.2–0.7 cm; pinnae 1–4 pairs; leaflets 3–7 pairs, blades obliquely oblong to elliptic, 1.5–4.5 × 0.5–2 mm, margins ciliate, reticulate veins prominent abaxially, apex obtuse or acute, surfaces glabrous or abaxial surface puberulent. Peduncles 0.5–1.5 cm. Inflo­rescences 10–30-flowered, axillary, globose capit­ula, solitary or fascicles of 2–5, 8–15 mm diam.; bracts linear to spatulate, 1/3–1/2 corolla length. Pedicels 0 mm. Flowers bisexual; calyx campanulate, lobes 5, 1/3–1/2(–2/3) corolla length, glabrous to puberulent; corolla purple, glabrous or puberulent, lobes 5, 1/5–1/4(–1/3) corolla length; stamens 10, filaments distinct to bases, white; ovary stipitate, glabrous; style attenuate at apex; stigma poriform. Legumes sessile or stipitate, straight, oblong, 20–40 × 5–8 mm, reticulate veins prominent, constricted or not between seeds, valves entire, margin prickly or unarmed, apex acute to acuminate or apiculate, faces glabrous; stipe 0.5–1 mm. Seeds 3–6, dark brown, elliptic or lenticular, 4.5–5 × 3.5–3.8 × 1.2–1.5 mm, testa porous, fissural line 50%.

Phenology: Flowering Mar–Sep; fruiting May–Oct.
Habitat: Dry, rocky plains and streambeds, arroyos, rocky limestone hills.
Elevation: 50–1400 m.

Distribution

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N.Mex., Tex., Mexico (Coahuila, Durango, Nuevo León, San Luis Potosí, Sonora, Tamaulipas).

Discussion

Variety texana is widely distributed in Brewster, McCulloch, Terrell, Travis, Uvalde, Val Verde, and Webb counties in Texas; a new report of this variety from adjacent New Mexico was collected at the environs of Whites City in Eddy County (R. G. Walter & J. M. Ricketson 426, MO!), just north and northeast of Guadalupe Mountains National Park, Texas.

Selected References

None.

Lower Taxa

None.