New combinations in the genus Didymoplexis (Orchidaceae; Epidendroideae; Gastrodieae), with a new variety of D. siamensis from Amami-Oshima Island, Japan Author Suetsugu, Kenji Department of Biology, Graduate School of Science, Kobe University, 1 - 1 Rokkodai, Nada-ku, Kobe, 657 - 8501, Japan; Author Hsu, Tian-Chuan Botanical Garden Division, Taiwan Forestry Research Institute, No. 53, Nanhai Rd., Taipei 100, Taiwan text Phytotaxa 2019 2019-01-15 388 2 174 178 http://dx.doi.org/10.11646/phytotaxa.388.2.4 journal article 10.11646/phytotaxa.388.2.4 1179-3163 13725214 Didymoplexis siamensis var. amamiana Suetsugu , var. nov. ( Figs. 1A , 2 ) Type:— JAPAN . Ryukyu Islands: Kagoshima Pref. , Amami-Oshima Island, Amami City, Naze, 5 May 2018 , Morita N 15-04 ( holotype : TNS , a flower in the spirit collection). Didymoplexis siamensis var. amamiana differs from D. siamensis var. siamensis only in lacking a pair of the long recurved stelidia on each side of its stigma. Additional specimens examined:— JAPAN . Ryukyu Islands : Kagoshima Pref. , Amami-Oshima Island , Amami City , Naze , 5 May 2018 , Morita N15-07 ( TNS , a flower in the spirit collection) ; Kagoshima Pref. , Amami-Oshima Island , Amami City , 13 May 2018 , Morita N15 - A ( KYO , a flower in the spirit collection) . Note:— The new variety is currently known only from a single population. About 20 flowering individuals were found in a dense forest dominated by Castanopsis sieboldii (Makino) Hatusima (1971: 223) . The new variety is not completely sympatric with D. siamensis var. siamensis , whereas D. siamensis var. siamensis can be observed a few hundred meters from the type locality.