Frailea, Cactaceae 3: 208. 1922 sec. Hunt 2006
- Type: Frailea cataphracta
Category E. No assessment of monophyly has yet been possible, because only a few species were sampled or no phylogenetic study has been conducted so far.
The combination of several Frailea names under Astrophytum by Halda & Malina (2005) reflects only a superficial similarity of seeds and flowers. This supposed close relationship had already been postulated by Buxbaum (1951),but has no phylogenetic support up to now. Frailea is one of several genera that, according to molecular phylogenies, have an isolated position within the Cactoideae, but the relationship to other clades is still not finally resolved (Hernández-Hernández & al. 2011).A