Etymology -From the Greek echinos meaning spiny and mastos meaning breast - spiny breast - referring to the tubercles.
Another denizen of the Southwestern United States and nearby Mexico is the genus Echinomastus. This is a relatively small group of cacti (5-9 species, according to Powell and Weedin, 2004) that are short, elongated globular plants. The stems seldom branch and for the most part do not exceed 12 inches in height. The stems are typically very heavily spined to the point of obscuring the stems. The spines rise from areoles on distinct tubercles arranged in rows. There exists a groove on the tubercles and extrafloral nectaries are sometimes present. Flowers are red, pink, cream-colored or even brownish and funnel shaped. The diurnal flowers, originating from the tips of the tubercles, come from the apex of the plant often fighting their way through a tangle of spines. The fruits dehisce either at the bottom or longitudinally when ripe.
The status of the genus Echinomastus is uncertain. In The New Cactus Lexicon (2006), the genus has been eliminated and all species placed under Sclerocactus. In The Cactus Family (2001), Anderson retains Echinomastus because of Porter's research (1999) showing distinct molecular differences from Sclerocactus.