Generic circumscription
The current checklist includes Pseudorhipsalis acuminata, P. alata, P. amazonica, P. himantoclada and P. lankesteri. Former Pseudorhipsalis ramulosa belongs to the separate genus Kimnachia. The synonymous generic names Wittia and Wittiocactus preserve the descriptive history of P. amazonica. [2-WWW]
Flower and pollen diversity
The 2017 chloroplast analysis confirmed a shared lineage for the genus after exclusion of Kimnachia ramulosa. This lineage exhibits distinct biological diversity. P. amazonica has blue tepals, whereas pollen tetrads have been reported in P. alata, P. himantoclada and P. lankesteri. These distinctive characters illustrate how much information a small epiphytic cactus flower can contain. [Korotkova et al. 2017, pp.12–13]