Autor: Ritter

” Flower enveloped with a hood “, designating the main feature of the genus, whose flowers are very distinct in that they begin by looking like a new stem segment, and as they develop they emerge out of the end and remain partly covered by the floral tube.
Monospecific genus of shrubby to treelike plants, strongly branched, with angular and segmented stems presenting notches, with well-defined areoles and with stiff, aciculate spines.
Flowers self sterile, at first tubular during the day, becoming bell-shaped at night, tearing the pericarp to get out, reddish or brownish, pollinated by bats. Fruits slightly angled, indehiscent, floral remains persistent, forming even if they have not been pollinated, but in this case, remaining sterile. Seeds ovate, coarsely tuberculate, black.
The monotypic genus Calymmanthium grows endemically in northeast Peru, between 950 m and 1800 m in altitude, in thickets, among shrubs, along rivers, on stony soils.
Peru (Amazonas, Cajamarca).

Currently only one recognised species:
– Calymmanthium substerile* F.Ritter 1968 (= C. subfertile)

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