This Chihuahuan Desert cactus bears a thick covering of short, bristly spines that completely conceal the green stems. Spines of echinocereus dasyacanthus
are usually cream or white in color, but yearly variations may result in faint, rainbow-like bands, hence the plant's common name; in this and some other respects it resembles the Arizona rainbow cactus
, for which the range is different, hence the two species can readily be distinguished; flower color is also quite different.
The beautiful flowers are bright yellow in the center, green at the base, lighter at the edges and underneath, and they may be 4 inches in diameter. Tepals may become pinkish as they age. Stamens have thin yellow filaments and small yellow anthers; stigma lobes (16 to 20) are dark green, atop a thick white style. Dull, greenish-purple fruits, around one inch in diameter, follow the flowers, which bloom in late spring.
Stems can reach heights of 15 inches, and a diameter of 4 inches. There are between 19 and 28 spines per areole, of which central spines number between eight and 12; they are round in cross-section, at most half an inch long.
Distribution of the Texas rainbow cactus is quite limited, though it can be locally abundant in its habitat of Chihuahuan desert scrub and grassland. The plant is found most readily in the Big Bend region of west Texas.