Shrubs, armed. Stems erect to ascending or scandent, broomlike, thorn-tipped, young growth sericeous. Leaves alternate, unifoliolate or odd-pinnate; stipules present, caducous or persistent, subspinescent; petiolate; leaflets 1 or 3, blade margins entire, surfaces usually sericeous, sometimes sparsely so. Inflorescences mostly solitary flowers, axillary, in distal unifoliolate leaves; bracts present; bracteoles absent. Flowers papilionaceous; calyx zygomorphic, campanulate, lobes 5; corolla yellowish; stamens 10, diadelphous; anthers basifixed; style glabrous basally, with pollen brush uniform in distal 1/2; stigma terminal, capitate, ciliate. Fruits legumes, sessile, laterally compressed, linear, elastically dehiscent, sericeous. Seeds 1–3(–6), lenticular; hilum apical. x = 8.

Distribution

Texas, n Mexico.

Discussion

Species 1.

Genistidium is native to the Chihuahuan Desert in western Texas and adjacent Mexico. It is readily distinguished from other woody native North American papilionoid genera by the combination of trifoliolate vegetative leaves and unifoliolate leaves on young branch ends that often harbor a solitary flower. The brushy or broomlike growth habit also is distinctive (M. Lavin and M. Sousa S. 1995).

Selected References

None.

Lower Taxa

Genistidium dumosum