This paper describes a new species of the genus Euonymus from Guizhou Province in southwestern China, Euonymus maotaiensis. The new species is morphologically similar to E. chloranthoides but can be distinguished by several key characteristics: broadly lanceolate leaves (as opposed to elliptic to oblong-elliptic), longer petioles (5-12 mm vs. 1-2 mm), longer peduncles (4-9 cm vs. 1-2 cm), 4- or 5-merous flowers (vs. strictly 5-merous), suborbicular petals with the upper half completely recurved abaxially (vs. planar petals), and indehiscent, 4-5 shallowly sulcate capsules (vs. 5-lobed capsules dehiscent to near the midpoint). These morphological differences are further supported by molecular phylogenetic analyses.
Wu et al. (Mon,) studied this question.