Begonia himalaica: A new species from Indian Eastern Himalayas

Repeated expeditions conducted in Arunachal Pradesh resulted in the discovery of a unique Begonia, Begonia himalaica D.Borah, Chowlu, A.Shenoy & Taram, belonging to sect. Platycentrum. It is close to Begonia rockii Irmsch. in having broadly ovate leaves, hairy petioles, and bearing inflorescences directly from the rhizome, but differs in having leaves glabrous adaxially and sparsely setose abaxially, irregular purplish red patches between veins, 20–40 cm long petiole covered with setose hairs, large glabrous navicular bracts at the base of the inflorescence, and glabrous ovary. This species is described here based on collections made in Chayang Tajo, East Kameng District of Arunachal Pradesh. The new species is assessed as Data Deficient according to IUCN Guidelines for Using the IUCN Red List Categories and Criteria.

Methods
The geographical scope of these expeditions covered the region between latitude 26°28′ N and29°30′ N, and longitude between 91°30′ E and97°30′ E. Upon collection, the specimens underwent meticulous processing, including the creation of mounted herbarium-sheets. This process adhered to the established methodologies outlined by Jain and Rao (1977). All the collected specimens were handled using conventional herbarium techniques, and type specimens have been officially deposited at ARUN and CAL (acronyms following Thiers 2024 continuously updated). Morphological examinations and measurements were conducted on both freshly collected and dried specimens. During this analysis, comparisons were drawn with the protologues of similar species found in India and its neighbouring countries. Additionally, reference was made to digital images of type specimens stored at renowned herbaria, such as BM, E, G, K, L, P, and PE. Provisional conservation status assessment was carried out as per the IUCN guidelines (IUCN, 2024).