The first record of the rare fern Pteris griffithii (Polypodiales: Pteridaceae: Pteridoideae) in the Bhutan Himalayas

Pteris griffithii Hook., one of the rarest fern species on the Indian subcontinent, is reported from Bhutan for the first time. The identity of this species was confirmed through morphological determination at the National Herbarium (THIM) of the National Biodiversity Centre (NBC) of Bhutan. It was found only in one location, in Gyelpozhing in eastern Bhutan, at an elevation of 521 m a.s.l. on 10 January 2016. Given that a very limited study of this species was conducted, the knowledge baseline with regard to its distribution is poor. It is also reported that this species has not been found for several years. The species is also considered to be very rare or critically endangered in some countries; however, there are no assessments on the International Union for Conservation of Nature (IUCN) Red List for this particular species. This paper attempts to provide baseline information considering its rarity and data deficiency. This species is also reported from the adjacent neighboring Indian state of Arunachal Pradesh as very rare, and also from Myanmar; however, confirmation of its presence in China is not clear at this time. Therefore, considering its data deficient status, we attempt to document it scientifically to create a knowledgebase pertaining to this particular species. Concurrently, this species merits further research to understand its distribution patterns in Bhutan and any related anthropogenic threats.