About Sclerocactus mesae-verdae (Boissev. & C.Davidson) L.D.Benson
Sclerocactus mesae-verdae is an unbranched, columnar cactus that reaches a maximum height of 20 cm and maximum diameter of 10 cm. This species has 13 to 17 longitudinal ribs, but its tubercules are inconspicuous. Each areole produces 7 to 14 radial spines that grow up to 13 mm long, plus 0 to 4 central spines that reach up to 15 mm long; central spines are usually straight, but are occasionally hooked. The flowers are bell-shaped to trumpet-shaped, growing up to 4 cm across and 3 cm in diameter. Their color ranges from white to yellow, with purple stripes running up the center of some outer tepals. When mature, the fruits are tan and cylindrical, reaching up to 10 mm long. The seeds of this cactus are black. One major population group of this species, containing around 1,000 plants, is found in Colorado. In New Mexico, 4 major population groups, holding a total of 4,000 to 10,000 plants, grow across four desert locations. These five major population groups are registered as threatened, and there are at most 10 total population groups remaining in the wild. This species has been officially listed as a threatened species federally since 1997, and globally since 2003. It grows most commonly on hilltops, benches, and hillslopes, in soil types ranging from gravelly to loamy to pulverulent clay.
