PLANT: Shrub 1–3 m tall, much branched, spreading, with yellowish tan to brownish bark, unarmed or with few thorns. LEAVES: pale green, somewhat succulent, spatulate to oblanceolate or obovate, acute or obtuse at the apex, 1–3(–5) cm long, 0.3–1(–1.5) cm wide, attenuate at base to a petiole 2–4 mm long. FLOWERS: abundant, in groups of 1–6(–8), on slender pedicels 5–20 mm long; calyx cup-shaped to tubular, 2.5–6 mm long, glabrous to sparsely pubescent, the lobes 5, triangular, 1/4 to 1/2 the length of the tube, their margins lanate-ciliate, glabrescent with age; corolla-tube narrowly obconic, 8–15 mm long, constricted at top of ovary and flared slightly at summit, 1.5–2 mm diameter at base, 3–4 mm diameter at top, greenish lavender or whitish, usually glabrous externally but sometimes with few scattered hairs, the lobes 5(4), rounded to oval or lanceolate, 2–4 mm long, spreading, densely ciliate-1anate with branched hairs which are apparent to the naked eye as a tiny white fringe; stamens unequal to subequa1, usually exserted; filaments adnate to about the middle of the corolla-tube, from rather densely to sparsely hairy on basal 1.5 mm of their free portion, adjacent corolla-tube also hairy; style longer than the stamens, usually exserted 2–3 mm. FRUITS: ovoid, 6–12 mm long, bright red, 8–30-seeded (Fig. 2H). n = 12. NOTES: River bottoms and alluvial flats in deserts of the Southwest (Fig. 3B): Coconino, Maricopa, Mohave, Pima, Pinal, Yuma cos. (Fig. 1I); 50–1000 m (100–3300 ft); Mar–May; s CA to TX, NV, UT; n Mex. REFERENCES: Windham, M.D. And G. Yatskievych. 2009. Vascular Plants of Arizona: Isoëtaceae. CANOTIA 5 (1): 27–29, 2009.