Desmanthus glandulosus

Herbs, usually erect, sometimes decumbent, sparsely branched, to 7 dm, base often woody. Stems sparsely pubescent on ridges or glabrous. Leaves 4–8 cm; stipules usually deciduous, rarely persistent, 1.2–6 mm, with small, membranous, erose auricles, glabrous or sparsely pubescent; petiole 4–10 mm; pinnae 3–6 pairs; nectary sessile, crateriform or flattened, between proximal pair of pinnae, usually also between distal pair of pinnae, sometimes between all pairs; leaflets 28–52, blades 4.2–7.4 mm, venation obscure except for eccen­tric midvein, surfaces glaucous, glabrous. Peduncles 1.8–3 cm, 1.8–3.5 cm in fruit. Heads (or condensed spikes) 1 per axil, 9–20-flowered; sterile flowers 3–7 per head; staminate and bisexual flowers 5–12 per head. Flowers: stamens 10; staminodia 6–8 mm; style not exserted beyond stamens. Legumes dark warm brown, straight or curved distally away from axis, linear, not constricted between seeds, dehiscent along both sutures, 5.8–10.6 cm × 3.4–4.6 mm, apex acute or apiculate.

Phenology: Flowering Jun–Sep, fruiting Jul–Oct.
Habitat: On limestone soils, oak-juniper woodlands, dry desert scrub.
Elevation: 100–2200 m.

Distribution

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N.Mex., Tex., Mexico (Coahuila).

Discussion

Desmanthus glandulosus is found infrequently in southern New Mexico and the mountains of western Texas.

Originally considered a variety of Desmanthus virgatus, D. glandulosus differs in having an erect, sparsely branched habit, usually more than one large, flattened nectary per leaf, and deciduous stipules. Also, the fruits of D. glandulosus are larger (to 10.5 cm, those of D. virgatus usually not exceeding 6 cm).

Selected References

None.

Lower Taxa

None.