2. Lycium cooperi A. Gray, Proc. Amer. Acad. Arts. 7: 388. 1868.
[E F]
Peach-thorn, Cooper’s desert-thorn
Shrubs erect, 0.6–2.5 m; bark usually purplish to reddish; stems densely glandular-pubescent. Leaves: blade spatulate to oblanceolate, 10–35 × 2–23 mm, surfaces usually densely glandular-pubescent. Inflorescences 2–3-flowered fascicles or solitary flowers. Pedicels 2–8 mm. Flowers (4–)5-merous; calyx narrowly campanulate, 4–14 mm, lobe lengths 0.5–1 times tube; corolla white or greenish yellow, sometimes purple-veined, tubular to funnelform, 8–15 mm, lobes 1.5–3 mm; stamens included to exserted. Berries greenish yellow to orange, ovoid, constricted at or distal to middle, 5–10 mm, dry, hard, strongly accrescent calyx usually rupturing with fruit growth. Seeds 6–10. 2n = 24.
Flowering Mar–May. Sandy washes to slopes (Mojave and Colorado deserts); 100–2000 m; Ariz., Calif., Nev., Utah.
Lycium cooperi occurs in western Arizona, southeastern California, southern Nevada (Clark and Esmeralda counties), and southwestern Utah (Washington County). It can be distinguished from the similar species L. pallidum and L. shockleyi by its dense, glandular pubescence and hard, constricted fruit.