Etymology -The name means "Isolated Cereus" describing the sparse distribution of individual plants in habitat.
A single species makes up the genus Isolatocereus. Although these plants closely resemble Stenocereus species and overlap geographically. As a result, taxonomists in the past have included the species I. dumortieri in Stenocereus under the same species name S. dumortieri. Differences in form - particularly the flowers - along with DNA research in the late 1990's are support for keeping this species in a separate genus. However, the New Cactus Lexicon, while stating this supporting information, places the species back into Stenocereus with no further explanation.
The plants themselves feature shallow ribs between 5 and 8 on stems up to 6inches (15cm) in diameter. Straight, heavy spines line the ribs in tightly-spaced areoles. The stems feature a bluish-green epidermis which is quite attractive. Overall growth of I. dumortieri is that of a tree branching low with long branches extending to nearly 50 feet (15m). Flowers are greenish-white and nocturnal, but remain open into the day.
The coloring, shape, and spine patterns of this plant make it desirable for cultivation, but the large size makes it more suitable as a landscape plant. This is not to say it isn't found in cultivation, but unless planted in the ground, one is not likely to ever see flowers on this species. In the wild, plants are widespread throughout central to southwestern Mexico.