Coleocephalocereus is a genus of columnar cacti in the family Cactaceae, order Caryophyllales, first described by Curt Backeberg in 1938. It comprises around a dozen accepted species (GBIF lists 16 descendant taxa; Plants of the World Online recognizes roughly ten species as of 2025), all endemic to eastern Brazil, occurring in the states of Minas Gerais, Espírito Santo, Rio de Janeiro, São Paulo, and Bahia.
Plants in this genus are erect or semi-erect columnar cacti. A defining feature of the genus is the cephalium: a specialized, wool- and bristle-covered structure that develops on mature stems and from which flowers and fruit are produced, a trait shared with several other Brazilian cephalium-forming cactus genera.
Coleocephalocereus species are characteristic plants of the inselbergs of the Brazilian Atlantic Forest (Mata Atlântica) — isolated, dome-shaped granite and gneiss rocky outcrops that rise above the surrounding forest. On these outcrops, where soil is thin or absent and conditions are hot and exposed, Coleocephalocereus can form a dominant part of the local flora, alongside other specialized inselberg vegetation.
Taxonomically, the genus has at times been split or merged with related segregate genera; GBIF treats Buiningia and Mariottia as synonyms of Coleocephalocereus, reflecting historical disagreement over how finely to divide this group of Brazilian cephalium cacti.
Distribution
All species of Coleocephalocereus are endemic to eastern Brazil, recorded from the states of Minas Gerais, Espírito Santo, Rio de Janeiro, São Paulo, and Bahia.
Ecology
The genus is characteristic of inselbergs — isolated, dome-shaped rocky outcrops — within the Brazilian Atlantic rainforest, where it can form a dominant component of the specialized flora that grows on these exposed rock formations.
Taxonomy Notes
Described by Curt Backeberg in 1938 (Blätter für Kakteenforschung). GBIF treats the segregate genera Buiningia Buxb. and Mariottia Guiggi as synonyms of Coleocephalocereus.
