Molecular phylogeny and morphology reveal a new epiphytic species of Habenaria (Orchidaceae; Orchideae; Orchidinae) from Nepal

Epiphytic Orchid Diversity along an Altitudinal Gradient in Central Nepal

Epiphytic orchids are common in subtropical forests, but little is known about the factors that determine their diversity. We surveyed two sites (north-facing Phulchowki and south-facing Shivapuri hills), in the sub-tropical forest in the Kathmandu valley, central Nepal. Along five transects per site, spanning an altitudinal gradient of 1525–2606 m a.s.l., we recorded all epiphytic orchids and the host species on which they were growing. The data were analyzed using a generalized linear model (GLM) and redundancy analysis (RDA). Species richness significantly decreased with increasing altitude and was higher in larger hosts and in places with high temperature. Species composition was affected by altitude, distance from the forest edge, host type, and precipitation. This study indicates that the most important factors affecting epiphytic orchid diversity was altitude, even if other factors were associated with patterns in composition. The low-altitude habitats with high species diversity are the best places for epiphytic orchids in this region. The altitudinal species richness and patterns in composition revealed by this study provide a baseline for further studies on epiphytic orchids.

Taxonomic revision of Habenaria josephi group (sect. Diphyllae s.l.) in the Pan-Himalaya

Species of the Habenaria josephi group in the Pan-Himalaya region are revised, based on their morphological characters and results of previous molecular phylogenetics. Eight distinctive species are recognised; key to the species, taxonomic descriptions, illustrations and distribution maps are provided. Habenaria josephi is re-instated, based on morphological and molecular evidence; H. wolongensis is synonymised with H. aitchisonii, a neotype for H. tibetica and the lectotypes for H. balfouriana, H. fargesii, H. glaucifolia and H. clarkei are designated.