Rhytidocaulon is a plant genus in the family Apocynaceae, first described in 1962.

[1][2] It is native to northeastern Africa and the Arabian Peninsula Species accepted by the Plants of the World Online as of February 2023:[3] 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.

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