Повторное открытие Elatostema ellipticum (Urticaceae) спустя 150 лет в Аруначал-Прадеше, Индия

The rare, monoecious, sub-ascending herb Elatostema ellipticum (Urticaceae), originally described by Weddell in 1869, has been re-collected from the Mishmi Hills, Arunachal Pradesh, India, in 2018 after an interval of over 150 years. This rediscovery confirms the species’ existence and its endemic status in the region. This information rectifies a historical error regarding the species’ type locality, confirming the correct origin and contradicting previous, erroneous attributions to Bangladesh, even though the holotype (K000741065) is housed at Kew. Morphological examination of the plant shows a strong match to the protologue and type material, highlighting diagnostic features like its succulent stems, narrowly elliptic leaves with finely serrulate margins, and distinctive linear-lanceolate, caducous stipules. Ecologically, E. ellipticum is restricted to the humid, shaded understory of subtropical riparian forests between 1200–1400 m a. s. l., requiring persistently moist, rocky substrates along streams in the Eastern Himalayas. Its known distribution is highly restricted to a single locality in the Upper Dibang Valley, where only 42 mature individuals were recently recorded. Given its extreme rarity, localized existence, and specific microhabitat requirements, the species likely qualifies as critically endangered (CR) under IUCN criteria, warranting urgent conservation attention, long-term in situ monitoring, and protective measures for its specialized riparian habitat.