About Echinocereus arizonicus Rose ex Orcutt
Echinocereus arizonicus Rose ex Orcutt is a cactus that typically grows in small clumps. Its stems are cylindrical, with 8 to 13 ribs, and measure 10 cm to 40 cm long by 5 cm to 10 cm wide (3.9 in to 15.7 in by 2.0 in to 3.9 in). Areoles on the stems are spaced 10 to 15 mm (0.39 to 0.59 in) apart. Spines on this cactus vary in form, and can be either straight or contorted. Each areole produces 1 to 8 central spines that are 15 to 50 mm (0.59 to 1.97 in) long, plus 7 to 14 radial spines that are 5 to 25 mm (0.20 to 0.98 in) long. Spines are initially yellowish to brownish in color, but fade to gray as they age. Flowers of Echinocereus arizonicus are deep red to bright orange-red, sometimes with a lighter yellowish-green center. They measure 5.5 cm to 7 cm long by 3.5 cm to 5 cm wide (2.2 in to 2.8 in by 1.4 in to 2.0 in), and have a 25 to 35 mm (0.98 to 1.38 in) flower tube that bears short spines and 2 mm (0.079 in) long hairs. Fruits are green with a brownish tinge, 20 to 30 mm (0.79 to 1.18 in) across, and contain white pulp. The chromosome count for this species is 2n = 22. This cactus occurs in desert scrub and grassland habitats of the Chihuahuan Desert, growing in Arizona and New Mexico in the United States, and Chihuahua in Mexico, at elevations ranging from 1400 to 1900 meters. It is found growing alongside Quercus turbinella, Quercus emoryi, Arctostaphylos pungens, Cercocarpus montanus, Nolina microcarpa, Dasylirion wheeleri, Agave chrysantha, Muhlenbergia emersleyi, Pinus monophylla, Juniperus pinchotii, and Rhus trilobata.
