Hymenophyllum paniculiflorum C.Presl

Chen, Cheng-Wei, Hsu, Tian-Chuan, Chao, Yi-Shan, Lu, Ping-Fong, Li, Chia-Wei, Tram, Nguyen Khanh Trinh, Nguyen, Ich Le Phuoc Thanh, Dang, Minh Tri, Luu, Hong Truong & Parris, Barbara, 2020, A newly recorded genus and twelve newly recorded species of ferns for Vietnam from Lang Biang Plateau, Phytotaxa 443 (2), pp. 121-143 : 132-133

Hymenophyllum paniculiflorum C.Presl ( Fig. 10 )

Type:— PHILIPPINES. Luzon, 1841, H. Cuming 214 (syntypes: B-20-0102266, image seen, BM-001044212!, BM-001044213!, BM-001044214!, E-00782189, image seen, GH-00021378, image seen, K-000420415!, MW-0731000, image seen, P-00623437, P-000623438, images seen, PNH, PRC).

Voucher specimens examined:— VIETNAM. Lam Dong Province, Lac Duong District , Da Chais Commune, Mt. Bidoup, 2100 m, 22 June 2018, T.- C. Hsu 10703 ( SGN!, TAIF!) ; Lam Dong Province, Lac Duong District , Lat Commune, Cong Troi station, 1600–1800 m, 24 September 2018, T.- C. Hsu 10975 ( SGN!, TAIF!) .

Additional specimens examined:— PHILIPPINES. Bukidnon Province, Mt. Kitanglad, 18 December 2012, L.- Y. Kuo 3551 ( TAIF!). Mountain Province, Bauko, around Mt. Data Hotel , 26 May 2009, L.- Y. Kuo 506 ( TAIF!). Negros Province, Canloan vocano, April 1910, E. D. Merrill 6917 ( BM!) . TAIWAN. Ilan County, Mt. Papokulu , 1900–2100 m, 24 September 2016, T.- C. Hsu 8587 ( TAIF!) ; Pingtung County, Mt. Iting , 2000 m, 29 January 2017, T.- C. Hsu 8898 ( TAIF!) .

Distribution:—This species is currently known from Malaysia, the Philippines, and Taiwan ( Parris et al. 1992; Hsu et al. 2019)

and possibly also distributed in Japan based on the data provided by Vasques et al. (2019). Due to the taxonomic difficulty within Hymenophyllum polyanthos (Sw.) Sw. (1801: 102) species complex, more studies are still needed to clarify its global distribution.

Ecology:—In Vietnam, this species has been found in cloudy ridge-top evergreen broad-leaved forests at the elevation of 1600–2100 m. There it grows as an epiphyte on upper trunks and canopy branches.

Note:—This species belongs to Hymenophyllum subgenus Mecodium Copel. ( Ebihara et al. 2006) and it has long been lumped within the widespread and polymorphic H. polyanthos (e.g., Liu et al. 2013; Nwe et al. 2017), but was recently reinstated based on both morphological and molecular data ( Knapp 2013; Hsu et al. 2019). Among the congeneric species in Vietnam, it could be recognized by the combination of glabrous and narrowly winged stipes, glabrous laminae, entire and crispate rachis and costa wings, entire and usually contorted ultimate segments, sori densely aggregate at lamina apex, and entire involucres.

Figures

FIGURE 10. Hymenophyllum paniculiflorum—A. Habit. B. Sori. C. Stipe and Rhizome. T.-C. Hsu 10703.