Species of Deamia are climbing or pendent shrubs. Their flowers have hairs and spines and are followed by red fruit with clear pulp.[2]
Taxonomy
The genus was erected by Nathaniel Lord Britton and Joseph Nelson Rose in 1920,[3] with the single species Deamia testudo. The name honours Charles C. Deam, a plant collector who sent the plant to Britton and Rose.[4] It was treated as a distinct monotypic genus until 1965, when Franz Buxbaum merged it into Selenicereus. Alexander Doweld revived the genus in 2002, adding the species then treated as Selenicereus chontalensis.[2]Molecular phylogenetic studies in 2017 (based on the two species then known) and in 2018 (three species) confirmed the monophyly of the genus.[2][5] It was placed in the tribe Echinocereeae, subtribe Pachycereinae.[5] It was one of the early diverging members of the tribe in the cladograms obtained in the 2018 study, with the species related as follows:[5]
Deamia
Deamia testudo
Deamia montalvoae
Deamia chontalensis
Deamia funis
Species
Two species were accepted in a 2017 study of the tribe Hylocereeae which revived the genus Deamia.[2] A third species was described in 2018.[5] A new species Deamia funis was discovered in 2022
