According to the 2003 key in the Flora of China, this species is distinguished from other entire-leaved rhubarbs in China with leaves having a wavy or crisped margin; R. wittrockii, R. webbianum, R. australe and R. hotaoense, by having less than 1 cm-sized fruit, yellow-white to greenish-white flowers, and the surface of the rachis of panicle covered in papilla. In many characters it is most similar to R. webbianum, and somewhat less so R. hotaoense.
There have been at least two studies investigating the karyotypy of this species, both studies focussing on the synonym R. undulatum. Both 2n=22 and 2n=44 have been found. It is possible that this karyotypic diversity indicates the existence of one or more cryptic species, because the polyploid forms would essentially be reproductively isolated.