Henckelia arunachalensis (Gesneriaceae), a new species from Patkai Hills of Arunachal Pradesh, India

Repeated expeditions conducted since 2018 in Arunachal Pradesh led to the collection of several taxa of Gesneriaceae, many of which are newly described. Among these, a peculiar species from the Patkai Hills of Arunachal Pradesh is described here as Henckelia arunachalensis, a species new to science. This new species is allied to Henckelia dibangensis but differs in its elliptic to obovate leaves with 9–13 pairs of lateral veins (vs ovate to ovate-elliptic with 5–8 pairs of lateral veins), erect to perpendicular cymes with 1–5 flowers (vs pendulous cymes with 1–2 flowers), broadly ovate to ovate lanceolate bracts (vs linear bracts), a leathery calyx, pale green and puberulous outside, glabrous inside (vs light green, glabrous calyx), and a purplish white corolla with white flaps (vs a pale pink corolla with no flaps). An extended taxonomic description, accompanied by photographs and ecological information, is provided.