Britton & Rose

Originates from the Greek words ancistron, meaning fishhook, and kaktos, meaning thistle, because of the strongly hooked central spines, characteristic of the genus.
A genus of globose to elongated plants, solitary, sometimes constricted at the base and having a tap root. Ribs more or less tuberculate, tubercles with nectar glands, one of the central spines, usually the longest, always hooked.
Flowers diurnal, rather small, self-sterile, creamy colour to greenish, lemon yellow or pale pink, usually pollinated by insects. Fruits clavate, fleshy, greenish. Seeds brownish to black, finely papillose.
The genus Ancistrocactus grows between the southeast of the United States and the northeast of Mexico, from 20 m up to 1700 m in  ltitude, in arid regions, on sedimentary, alluvial, limestone, sandy, clay or rocky soils, including gypsum soils (Ancistrocactus brevihamatus) on hills, in cracks in the rocks, in the shade of shrubs and among grasses.
Mexico (Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Tamaulipas), USA (Texas).

currently 3 recognised species plus a subspecies:
– Ancistrocactus brevihamatus* (Engelm.) Britton & Rose 1923
– Ancistrocactus brevihamatus subsp. tobuschii (W.T.Marshall) Doweld 1999
– Ancistrocactus megarhizus (Rose) Britton & Rose 1923
– Ancistrocactus Scheeri* (Salm-Dyck) Britton & Rose 1923
*Note that A megarhizus is sometimes considered a subspecies of A. scheeri.


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