Rediscovery of Primula cooperi Balf.f. (Primulaceae), a species endemic to Sikkim, Eastern Himalaya

In this study, we report the rediscovery of Primula cooperi Balf.f. whose
existence was seen as a mystery until now. It was first collected in the
year 1913 from North Sikkim by Roland Edgar Cooper. Since its first
discovery, it has not been rediscovered again. It was declared extinct as
its type locality had been repeatedly surveyed without success. Based on
our recent rediscovery, characteristics of the species is updated
supported by photographs and measurements. The latest IUCN Red List
categorised its conservation status as Critically Endangered. Lastly, a
phylogenetic analysis revealed P. cooperi as a member of P. sect.
Proliferae of the sub-genus Aleuritia with P. prenantha being its closest
sister taxon. Morphologically, it has close affinities with P. brachystoma
and P. polonensis.