Autor: Britton & Rose
The name is an anagram of Mendoza, in Argentina, the province where the genus was first found.
Monotypic genus of plants generally solitary (branching from the base only very rarely), at first globose, becoming columnar, with numerous ribs (up to 30), areoles very close. Spines highly polymorphic, especially between young and adult plants. Flowering areoles with bristles, hairs and spines which are longer and robust.
Flowers diurnal, self-sterile, tubular slightly zygomorphic, appearing near the apex, scarlet red, pollinated by hummingbirds (Patagona gigas), but considering the ease with which the pollen grains are released, I would add a possible and even probable anemophily. Fruits globose, hairy, becoming dry and cracking from the top when ripe. Seeds shiny, wrinkled and pitted, brownish black.
The monotypic genus Denmoza grows in full sun, from 600 m up to approximately 3500 m in altitude, on rocky hills, stony slopes, on rocky but also sandy soils, in foothills situated east of the Andes. In habitat, plants tend to heliotropism.
Argentina (Catamarca, La Rioja, Mendoza, Salta, San Juan, Tucuman).
Currently only one recognised species (and a possible subspecies?):
– Denmoza rhodacantha* (Salm-Dyck) Britton & Rose 1922