The rediscovery of Passiflora kwangtungensis Merr. (subgenus Decaloba supersection Disemma): a critically endangered Chinese endemic

Abstract. Passiflora kwangtungensis is a critically endangered Chinese species known from Guangxi, Guangdong, and Jiangxi Provinces. The species belongs to Passiflora subgenus Decaloba, supersection Disemma, section Octandranthus. Field observations decreased rapidly during the 1970s to 1980s, and it was suspected that this species might have been extirpated due to repeated deforestation events throughout southern China. In recent years, however, small isolated populations of this species have been rediscovered in Hunan Province, representing new locality records for Passiflora kwangtungensis. New herbarium collections, color photographs, and silica gel collections have provided an unexpected opportunity to examine the evolutionary significance of this species. The current study presents a revised morphological description of Passiflora kwangtungensis based on fresh material, along with an updated distribution map. Using nrITS sequence data, preliminary insights into the phylogenetic position of Passiflora kwangtungensis are presented. Molecular data support the placement of Passiflora kwangtungensis within supersection Disemma section Octandranthus. However, the exact placement of Passiflora kwangtungensis within this lineage is unclear. The nrITS data suggest that Passiflora kwangtungensis may be sister to a clade containing Passiflora from China, Nepal, India, and Southeast Asia. Morphologically, Passiflora kwangtungensis displays the most similarity Passiflora geminiflora (Nepal, India) and Passiflora henryi (China). Lastly, conservation status and recommendations are made for Passiflora kwangtungensis following the IUCN Red List Criteria, where this species is classified as CR C1+C2a(i); D.