Abstract
The ferns family Hymenophyllaceae is one of the most interesting basal clades of ferns, which is widely distributed in tropical and subtropical regions, less common in temperate latitudes of both hemispheres. This work deals with the taxonomic study of the representatives of the subfamily Trichomanoideae, which according to the classification of PPG 1 (2016) in the region are represented only by three genera. Following the style of the treatment of the genus Hymenophyllum, this paper is the second report of our studies of the filmy ferns from the Pan-Himalaya which is a part of the ongoing “Flora of Pan-Himalaya” project. In the present account, the taxonomy of three genera of Hymenophyllaceae: Crepidomanes, Didymoglossum, and Vandenboschia from the Pan-Himalaya are carefully revised based on morphological characters and recent works in the region. Herbarium materials kept in the National Herbarium (PE) have been fully studied and compared with collections from the Himalayas kept in European herbaria (K, BM, E). The generic and infrageneric classifications follow those of Ebihara et al. (2006) which recognized only nine genera. In the Himalayas, only four genera represented, i. e., Hymenophyllum (10 species), Crepidomanes (5 species), Didymoglossum (1 species), and Vandenboschia (2 species). The synopsis includes a key for species identification, standard taxonomic citations for the genus, sections, species. For each taxon as well as of each synonym are verified and indicated, necessary literature citation, morphology descriprion and citation of the reprehensive specimens from the Pan-Himalaya are recorded, overall distribution is mentioned and distribution in the Flora of Pan-Himalaya area is mapped. Although this is only a precursor of the ongoing “Flora of Pan-Himalaya” project, it is useful for identification of new collections from the area, and provides basic information for the conservation and ecological studies of the filmy ferns from the Himalayas, a very sensitive area to global changes. Crepidomanes parvifolium and Didymoglossum sublimbatum in this region are critical endangered concerning their small populations and limited distribution.
Highlights
One species was found in Pan-Himalaya, more than 20 species are distributed throughout the tropics, mainly in the New World
In the new classification system of Ebihara et al (2006), it was placed into the genus Didymoglossum because of the lack of submarginal false veinlets
General distribution: China (Guangdong, Guangxi, Guizhou, Hainan, Jiangxi, Taiwan, Zhejiang, Sichuan, Xizang, Yunnan), Japan, Bhutan, C and E Nepal, Myanmar, NE India (Himalayas, Sikkim, Darjeeling, Kameng, Subansiri, Siang, Tirap, Changlang), Laos, Thailand, Cambodia, Malaysia, The Philippines, Indonesia, Pacific Islands (Micronesia)
Summary
For the taxonomic treatment of the genus Humenophyllum, see Nwe and Zhang (2017, Turczaninowia, 20, 2: 75–96). (= Didymoglossum hymenoides (Hedw.) Copel.), chosen by Morton (1968). Filiform, frequently branching, densely covered with dark hairs, root absent, root-like shoot present. Usually simple, or sometimes lobed to pinnatifid, elliptic to narrowly ovate, often reduced the stipe; venation catadromous, often flabelliform, submarginal false veinlets absent, longitudinal false veinlets parallel to the true veins present, cell walls thin and straight. One species was found in Pan-Himalaya, more than 20 species are distributed throughout the tropics, mainly in the New World
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
