Vaupel, Die Kakteen 2: 82. 1926.
Now treated as Pfeiffera micrantha (Vaup) Heath , Calyx 4
(4): 158. 1994
Detail from Kimnach in C&SJ (US) 55: 177-182. 1983
Attached to the lectotype sheet is a note from Vaupel to Rose dated
October 1920: "I enclose a slip and a flower of Cereus micranthus.
I have described the plant as Cereus because I could not otherwise
correctly classify it, and intended later to put it in its proper place
on working up the entire group. It is of course not a Cereus
in the stricter sense but belongs to the vicinity of Rhipsalis."
Later, Vaupel (1926) placed the species in Rhipsalis, but as
R. asperula Vaup., because the original specific name had been
pre-empted by R micrantha (H.B.K.) DC.