R. micrantha discussion (Ken Friedman, approx. 1980)
The R. micrantha (HBK) de Candolle complex is a confusing group of Rhipsalis species. Rose listed R. micrantha, R. roseana Berger, R. tonduzii Weber and R. werklei Berger--all from Costa Rica.
Rose noted that R. wercklei was closely related to R. tonduzii from which he was unable to distinguish it (see his p. 240). Backeberg seems to have picked up his own reference to R. wercklei directly from Berger. Barthlott (1977b), who did a lengthy study of the R. micrantha complex (1974), believed then that R. wercklei and R. tonduzii were both synonymous with R. micrantha.
A supposed specimen of R. wercklei which, although it had not flowered at the time I wrote this in the late 1970s, was a dead ringer for Selenicereus wercklei Weber depicted by Rose with two photographs. But R. wercklei and S. wercklei were reported to have come from Costa Rica, a suspicious coincidence to say the least.
Even further confusion results from the Britton and Rose comment about S. wercklei: "it resembles some species of Rhipsalis in its epiphytic habit and in its long, slender, naked branches, but not in flower." The flower is definitely not the same as that of R. wercklei described elsewhere by Rose (see Rose, p. 240). Perhaps the descrepancy adds credance to the argument that R. wercklei is in fact linked to R. tonduzii.
R. roseana Berger was described as "decidedly distinct from R. wercklei." (see Rose, p. 246). As indicated above, R. wercklei from Costa Rica was suspected by Rose of being different from R. tonduzii and both R. tonduzii and R. wercklei were seen as "close to" R. micrantha. Barthlott (1977b) believed that R. roseana was a Columbian form of R. micrantha.
Commercial R. micrantha has thin stems that are flat to three or four angled. White flowers, white fruits.
(1999) Much work was done by Barthlott on this group after I wrote the previous review. The results can be seen in the species listed below.