Monotropastrum humile (D. Don) H. Hara
First description by Don (1825) as Monotropa humilis, transferred to Monotropastrum humile through Hara (1961). Accepted by Wallace (1975). Monotropastrum humile is superficially very similar to Monotropa uniflora and has been confused with it very often. It differs from Monotropa uniflora by its smooth unilocular overy, 6-13 parietal placentas, anthers opening by an elliptic lid, a bluish stigma, a berry as fruit, oval seeds without appandages, and an earlier flowering time (after Hara 1965).
There is still some debate on the taxonomic status of the variety of this species, Monotropastrum humile var. glaberrimum (Hara 1965). While Qin and Wallace (2005) consider it as a synonym to a variabel M. humile, Tsukaya et al. (2008), investigating morphological as well as molecular features, suggest this taxon to be referred to even another genus, namely Cheilotheca. However, they hesitate to formally transfer it until more molecular data are available. In fact, Keng & Hsieh (Hsieh 1978) already called the taxon Cheilotheca humilis var. glaberrima in the Flora of Taiwan. Since several papers (Yokoyama et al. 2005, Yamada et al. 2008, Matsuda et al. 2011) distinguish between two varieties (the third var. tripetalum of Hara (1965) has been synonymized by Wallace (1975) together with var. glaberrimum, and was not used since), and following the arguments given in Tsukaya et al. (2008), we accept Monotropastrum humile var. glaberrimum until more data are available.