2. Nephoanthus prostratus (C.Hansen) C.W.Lin & T.C.Hsu, comb. nov. (Fig. 6)

Basionym: — Phyllagathis prostrata Hansen (1990: 39) .

Type: — VIETNAM. Quang Tri Province: Dông Tan Pe, 15 June 1939, E.Poilane 30047 (holotype: P-02274756 image!; isotype: P-02274757 image!) .

Distribution and ecology: —Central and Southern Vietnam, also found in Hainan Island, in China (see http://ppbc. iplant.cn/tu/6969375; unfortunately, these plants from the photos from Hainan Island were not collected). It occurs in riparian habitats on shaded riverbanks, steep slopes or on granite cliffs at an elevation of 250–1,200 m.

Additional specimens examined: — VIETNAM. Quang Tri Province: “ Lang Khoai ”, 10 June 1924, E. Poilane 10783 (P image!) . Da Nang City: “Tourane”, May–July 1927, J. Clemens & M. S. Clemens 3479 (P image!) . Quang Nam Province: Tramy, 500 m, 24 February 1941, E. Poilane 31631 (P image!) . Phu Yen Province: Song Hinh District, Buon Kit, 12°49’52”N 108°53’57”E, 269 m, 25 June 2014, H. T. Luu, G. Tran & C. T. Do PY0041 (SGN!) . Dak Lak Province: M’Drak District, Cu Kroa Commune, 12°41’40”N 108°53’33”E, 750 m, 20 June 2020, H. T.Luu, T. Q. T.Nguyen, Q. D.Nguyen & H. C.Nguyen VT-VP-0286 (SGN!); M’Drak District, Cu Kroa Commune, 12°41’55.47”N 108°53’8.04”E, 610 m, 23 June 2020, Q. D.Nguyen VT-VP-0409 (SGN!) . Khanh Hoa Province: Khanh Son District, Khanh Trung Commune, 12°2’32”N 108°59’43”E, 1152 m, H. T. Luu et al. KH 0654 (SGN!); Dien Khanh District, Hon Ba, 21 June 2004, D.D.Soejarto & T. N. Ninh 13261 (P image!) .

Note: —This is a very attractive species that has become a popular greenhouse plant among indoor plant enthusiasts around the world. Because of its compact growing, rugose foliage with silvery variegation, it is often for sale on social networks. Although this species seems not rare in the nature, its population could be threatened due to commercial trade for ornamental plants.