Rhytidocaulon
Rhytidocaulon is a plant genus in the family Apocynaceae, first described in 1962. It is native to northeastern Africa and the Arabian Peninsula.
;Species
Species accepted by the Plants of the World Online as of February 2023:
- Rhytidocaulon arachnoideum
- Rhytidocaulon baricum
- Rhytidocaulon ciliatum
- Rhytidocaulon elegantissimum
- Rhytidocaulon fulleri
- Rhytidocaulon macrolobum
- Rhytidocaulon mccoyi
- Rhytidocaulon molamatarense
- Rhytidocaulon paradoxum - Ethiopia
- Rhytidocaulon piliferum - Somalia
- Rhytidocaulon pseudosubscandens
- Rhytidocaulon richardianum - Somalia
- Rhytidocaulon sheilae
- Rhytidocaulon specksii
- Rhytidocaulon splendidum
- Rhytidocaulon subscandens - Somalia, Ethiopia
- Rhytidocaulon tortum - Arabia
Phylogenetic studies have shown the genus to be monophyletic, and most closely related to the genus Echidnopsis which inhabits the same region. Marginally more distantly related is a sister branch comprising the genus Pseudolithos and the widespread Caralluma stapeliads of North Africa.