Aphyllorchis caudata Rolfe ex Downie 1925
Aphyllorchis caudata was described by Rolfe (Downie 1925) from Doi-Sutep, Thailand. Rolfe (Downie 1925) also listed a collection from Szemao, Yunnan, China. A. caudata grows at altitudes from 900 to 1.200 m. A. montana is similar to this species but has smaller sepals and the apex is obtuse to subacute while A. caudata has sepals bigger than 3 cm and the apex is long cuspidate (Efloras 2021). Tian et al. (2013) proposed the synonymisation of A. caudata with A. annamensis, which was described by Averyanov (1996, publ.1997) as an endemic species to Vietnam. Averyanov (1996, publ.1997) had already noted the resemblance to A. caudata, describing differences in the petals and that the lip is long caudate at the tips. A. caudata occurrs in Thailand, Vietnam and South China (POWO 2021).