Mesa Verde cactus
[Coloradoa mesae-verdae Boissev. & C.Davidson, more]
Stems usually unbranched (occasionally 2-3-branched), usually pale green, depressed-spheric to ovoid, usually 3.2-11(-18) × 3.8-8(-10) cm, somewhat glaucous; ribs 13-17, tubercles inconspicuous. Spines not obscuring stem, usually only radial; radial spines 7-14 per areole, spreading, straw colored, 6-13 mm, less than 1 mm diam.; central spines 0(-4) per areole (very rarely 1 abaxial central spine per areole hooked, 7-15 mm, brown). Flowers funnelform to campanulate, 1-3.5 × 1-3 cm; outer tepals with purple midstripes and cream or gold (rarely pink) margins, oblanceolate, 10-25 × 5-8 mm; inner tepals yellow to cream (rarely pink), oblanceolate, 15-30 × 5 mm; filaments pale yellow or white; anthers yellow. Fruits indehiscent to irregularly dehiscent, green, becoming tan at maturity, short cylindric, (4-)8-10 × 7-9 mm. Seeds black, 2.5-3 × 3-4 mm; testa cells convex but somewhat flattened apically. Flowering late Apr-early May. Alkaline, clay badlands, mat saltbush communities; of conservation concern; 1500-1700 m; Colo., N.Mex. Sclerocactus mesae-verdae is characterized by its relatively short radial spines and the general absence of central spines. In addition, no other Sclerocactus in Colorado or New Mexico has flowers that are cream to yellow (or pale pink). Sclerocactus mesae-verdae is in the Center for Plant Conservation´s National Collection of Endangered Plants.