Autor: (Backeberg) Backeberg

“Isolated candle”, because the populations of the genus are very scattered, well separated and isolated from each
A genus of treelike plants, columnar, heavily branched, developing a short trunk. Stems with few ribs (5-7), areoles close-set, spines aciculate.
Flowers nocturnal, self-sterile, remaining open the following morning, numerous, appearing in chains on the tallest stems, tubular, white with outer tepals reddish, pollinated by bats (Choeronycteris mexicana, Leptonycteris curasoae, L. nivalis). Fruits egg-shaped, unarmed, red – orange with red pulp, dehiscent. Seeds small, elongated, warty, shiny, black.
The monotypic genus Isolatocereus grows endemically in Central Mexico, in valleys or on hills of basalt, forming true forests, in a vegetation of matorral, between 300 m and 2300 m in altitude. It is used locally for making quickset hedges.
Mexico (Aguascalientes, Guanajuato, Guerrero, Hidalgo, Jalisco, Mexico D.F., Michoacan, Morelos, Oaxaca, Puebla, Queretaro, San Luis Potosi, Veracruz, Zacatecas).

Currently only one recognised species:
– Isolatocereus dumortieri* (Scheidw.) Backeb. 1942

References: "TAXONOMY of the CACTACEAE" -  ISBN 978-84-617-3723-9 (Vol. 1)