Didymoplexis siamensis var. amamiana Suetsugu, 2019

Suetsugu, Kenji & Hsu, Tian-Chuan, 2019, New combinations in the genus Didymoplexis (Orchidaceae; Epidendroideae; Gastrodieae), with a new variety of D. siamensis from Amami-Oshima Island, Japan, Phytotaxa 388 (2), pp. 174-178 : 177

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.

Figures

FIGURE 1. A. Didymoplexis siamensis var. amamiana from the type locality. B. Didymoplexis siamensis var. siamensis from Amami- Ohshima Island. Photograph by Hidekazu Morita.

FIGURE 2. A. Didymoplexis siamensis var. amamiana (drawn from the holotype). A. Flower. B. Flattened perianth tube. C. Column. D. Lip. E. Anther cap. Bar = 1 mm. Drawing by Kumi Hamasaki.