Updated checklist of orchids of Himachal Pradesh (Northwest Himalaya) and the adjoining plains

Himachal Pradesh is an Indian state located in northwestern part of the Himalaya, a global biodiversity hotspot. An up-to-date checklist of orchids is provided for this state, along with the plains of five states/ Union territories (Jammu and Kashmir, Punjab, Haryana, Uttar Pradesh, Uttarakhand), surrounding it from northwest to southeast. The study area lies between 29°34´–33°12´ N latitude and 75°06´–79°04´ E longitude, and experiences vast altitudinal variation (250–7000 m a.s.l.). A total of 107 taxa (106 species and one variety) belonging to 47 genera are documented. Ninety-seven species are distributed in Himachal Pradesh and 23 in the adjoining plains. Majority of species are monsoon blooming ground-growers, which are distributed in mid-hills (1500–3200 m a.s.l.). A few species viz. Cypripedium himalaicum, Dactylorhiza viridis, Galearis spathulata, Gymnadenia orchidis, Hemipilia chusua, Herminium monorchis, and H. pugioniforme find distribution even beyond 4200 m elevation. Seven of the terrestrial species exhibit leafless mycoheterotrophic/ partial mycoheterotrophic life mode. Only twenty species grow in tree canopies as epiphytes; these flower during spring to early summer and distributed mainly in low hills and the plains (300–1500 m). Details on distribution range, phenology, and district-wise occurrence of various orchid species in the study area are provided, along with a small note on conservation.