苦苣苔科凹柱苣苔属在越南的发现及水晶凹柱苣苔的补充描述

Discovery of a rare genus Litostigma (Gesneriaceae) from northern Vietnam with the supplementary description of L. crystallinum

中越边境喀斯特地区有着异乎寻常的植物多样性,已经成为全球生物多样性研究和保护的热点区域,近年来在该区发现了多个苦苣苔科植物的新种或新属。凹柱苣苔属是2010年才被建立的新属,该属的花与叶相比,花较大,叶相对较小,叶片边缘稍外卷,花序仅单花,柱头盘状或凹坑状,蒴果长椭球形而有别于苦苣苔科的其他属。凹柱苣苔属为喀斯特专性植物,目前仅包括分布于黔西南的凹柱苣苔和分布于滇东南的水晶凹柱苣苔两个物种。作者在开展中越边境喀斯特地区植物多样性调查时,在越南北部的河江省发现了水晶凹柱苣苔,基于该新发现居群的植物标本,对其进行了补充描述,确认其花期为11月—12月,并对该物种濒危状况进行了重新评估,同时提供了野外生态照片以资辨认。目前,越南已记录苦苣苔科植物32属150余种,凹柱苣苔属在越南北部的发现,不仅丰富了该国苦苣苔科植物的多样性,再一次充分证明了中越边境喀斯特地区是一个完整的植物区系地理单元,而且为稀有的水晶凹柱苣苔提供了更加丰富的野外本底资料,对其将来的深入研究和保护具有重要的生物地理学和保护生物学意义。

The Sino-Vietnamese limestone karsts show specially high levels of plant diversity among Indo-China floras,and also are biodiversity hotspots in the world,and many new species or genera of Gesneriaceae have been found there recently. The genus Litostigma Y. G. Wei,F. Wen & M. M?ller( Gesneriaceae) was reported firstly from limestone areas of southwestern China in 2010,included two species,namely Litostigma coriaceifolium Y. G. Wei,F. Wen & M. M?ller( Typus generis) from southwestern Guizhou,and Litostigma crystallinum Y. M. Shui & W. H. Chen from southeastern Yunnan. We fortunately found Litostigma crystallinum from Ha Giang,northern Vietnam,and reported here to sufficiently know the diversity of Gesneriaceae in Vietnam. The description of Litostigma crystallinum was supplemented base on the collections from Ha Giang,northern Vietnam,and the habitat photos were also provided. The discovery of Litostigma crystallinum from northern Vietnam demonstrates the closely floristic relationship between northern Vietnam and southern China once again. The new localities are also very important for the conservation of Litostigma crystallinum.