PLANT: Shrub 1–3 m tall, rigidly branching, thorny; young branches silvery gray, scarcely to densely glandular-pubescent; old branches dark brown to black, glabrescent; thorns straight. LEAVES: linear-spatulate to obovate or oblong-lanceolate, 5–30(–35) mm long, 2–5(–12) mm wide, acute to rounded at apex, tapering to a petiole 1–2 mm long or sessile, bright green, glabrous or minutely puberulent, sometimes with white veins, fascicled in groups of 3–6. FLOWERS: pendant, solitary or in pairs at the leaf fascicles (Fig. 2D); pedicels minutely puberulent, 1–7 mm long; calyx campanulate, 4–9 mm long, minutely glandular-puberulent; calyx-lobes 5, as long as the calyx tube or up to 2 times as long as the tube, subulate to linear-lanceolate, acute; corollatube greenish white, 6–12 mm long, glabrous to sparsely puberulent externally; lobes 5, greenish white to pale lilac with dark veins, ovate to oblong, sparsely to densely ciliolate, 2–5 mm long, rotate to reflexed; stamens subequal, barely exserted 2009 VASCULAR PLANTS OF ARIZONA 21 to exserted 2–4 mm; filaments adnate to corolla-tube from base to a little below the middle, pilose from near base of the corolla to 4 mm on free portion, or almost glabrous; style included or 1–4 mm longer than the stamens. FRUITS: constricted below the middle, yellowish to brownish when ripe, 6–10 mm long, notched at the apex; upper part of each locule bearing 1–2 seeds enclosed in an indurated endocarp; lower part fleshy, bearing 1–5 abortive ovules. N = 12. NOTES: Lower Sonoran Desert in AZ, in washes and in flats: La Paz, Maricopa, Pima, Pinal, Yuma cos. (Fig. 1F); 250–750 m ( 800–2500 ft); mainly Feb–Apr, occasionally at other times; Son. Mex. REFERENCES: Windham, M.D. And G. Yatskievych. 2009. Vascular Plants of Arizona: Isoëtaceae. CANOTIA 5 (1): 27–29, 2009.