Echinocereus merkeri

Echinocereus merkeri is a species of Echinocereus.

Background
Cespitose; joints erect, 12 to 15 cm. in diameter, light green; ribs 8 or 9, sinuate; radial spines 6 to 9, white, shining; central spines 1 or rarely 2, often yellowish, larger than the radials, red at base; flowers purple, about 6 cm. long; inner perianth-segments short-oblong, 3 cm. long, rounded at apex, sometimes mucronate; scales on ovary 2 to 3 cm. long, ovate, acuminate, bearing 2 to 5 long spiny bristles in their axils. Distributed in Durango to Coahuila and San Luis Potosi, Mexico.