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

Shawn E Krosnick,Yunfei Deng,Xun-Lin Xun-Lin Yu

doi:10.3897/phytokeys.23.3497

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.

Highlights

The genus Passiflora L. consists of ca. 526 species (Feuillet and MacDougal 2003) with native ranges throughout the southern United States, Mexico, Central, and South America
P. kwangtungensis is resolved as sister to the remaining species in clade. Passiflora altebilobata (clade E), jackknife support for the position of P. kwangtungensis and P. altebilobata Hemsl. relative to remaining species is
To further explore the placement of P. kwangtungensis as sister to the remainder of clade E, another heuristic search using the same parameters was performed with P. altebilobata removed from the dataset

Summary

Introduction

The genus Passiflora L. consists of ca. 526 species (Feuillet and MacDougal 2003) with native ranges throughout the southern United States, Mexico, Central, and South America. Subgenus Decaloba supersection Disemma (Labill.) J.M. MacDougal & Feuillet contains the remaining 21 species found throughout Asia, Southeast Asia, and the Austral Pacific (Krosnick and Freudenstein 2005). The native Passiflora in China exhibit high levels of endemism, seldom display overlapping distributions, and are in general extremely rare. Of those 13 species found in China, Passiflora wilsonii Hemsl., P. eberhardtii Gagnep., P. jugorum W.W. Sm. and P. tonkinensis W.J. de Wilde are the only species found in surrounding countries as well, and these primarily represent narrow range expansions beyond the borders of China south into Vietnam, or west into Myanmar or India

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