Genus honouring Prof. Werner Rauh (1913-2000), German botanist, explorer and director of the Botanical garden of the University of Heidelberg in Germany, specialist of the Peruvian flora (and Madagascar).
A genus of shrubby columnar plants, branching usually from the base, forming groups of erect bluish green stems, with 5-6 tuberculate ribs. Tubercles with very characteristic facets, areoles woolly. Radial spines short, sometimes pectinate, 2 centrals sturdier and longer.
Flowers nocturnal, self-sterile, bell-shaped to rotate, appearing near the apex of stems, with floral tube bearing small scales and frizzy brown hairs, white, pollinated by bats (Anoura caudifer, A. geoffroyi, Glossophaga soricina). Fruits egg-shaped, fleshy, raspberry red to violet purple, with longitudinal dehiscence from the base, pulp orange to scarlet, floral remains persistent. Seeds rather small, elongated, black, shiny, finely pitted and striate.
The monotypic genus Rauhocereus grows endemically in northern Peru, from approximately 400 m up to 2500 m in altitude, often among a dense vegetation of dry forests and shrubs, in a loamy soil.
Peru (Amazonas, Cajamarca, Lambayeque).
Currently 1 only recognised species, plus a doubtful subspecies:
– Rauhocereus riosaniensis* Backeberg 1958
– Rauhocereus riosaniensis subsp. jaenensis (Rauh) Ostolaza 1998
References: "TAXONOMY of the CACTACEAE" - ISBN 978-84-617-3692-8 (Vol. 2)