【摘要】 水韭属（Iso?tes）是一类世界广布的石松类植物，本文报道了在云南省发现的一个新的水韭属居群。该居群为六倍体群体，染色体数目为66条。利用扫描电镜对其进行孢子观察，发现其大孢子赤道面直径为470～500μm(平均480μm)，近极面和远极面纹饰均为网格状，小孢子表面为棘刺状纹饰，与之前国内记载的六倍体物种东方水韭（Iso?tes orientalis Hong Liu&Q. F. Wang）不同，基于叶绿体基因组数据重建的系统发育结构支持该物种是一个独立物种，最终将其确定为一个新物种，命名为青锋水韭（I. fengii Y. F. Gu&Y. H. Yan）。青锋水韭与二倍体云贵水韭（I. yunguiensis Q. F. Wang&W. C. Taylor）在叶和大孢子形态上较为相似，但后者的小孢子表面为瘤状突起且孢子囊为卵形；而与六倍体宽叶水韭（I. japonica A. Braun）的区别在于后者的小孢子表面光滑。青锋水韭目前仅在云南省紫溪山森林公园发现两个居群，且数目很少，根据IUCN红色名录评估标准，将青锋水韭评为极危（CR）等级。本文编制了中国已知水韭属物种的分种检索表，以期为本属物种的鉴定和保护工作提供参考。更多还原

【Abstract】 The genus Iso?tes is a widely distributed group of lycophytes. This paper reports on the discovery of a new population of Iso?tes in Yunnan Province, China The population is hexaploid and contains 66 chromosomes. The spores were observed using scanning electron microscopy, which revealed several unique characteristics. Notably, the megaspores(diameter 470 – 500 μm, mean of 480 μm) exhibited a reticulate ornamentation on the proximal and distal surfaces, while the microspores displayed an echinate pattern to their surfaces. These characteristics distinguish the new species from the previously documented hexaploid species in China, I. orientalis Hong Liu & Q. F. Wang. Phylogenetic analysis based on chloroplast genome data further supported recognition of this distinct species. Thus, we identified and named the new species I.fengii Y. F. Gu & Y. H. Yan, sp. nov. in the present paper. Morphologically, diploid species I. yunguiensis Q. F.Wang & W. C. Taylor shares similarities in leaf and megaspore characters with the new species but differs by laevigate-granulate microspores and ovate sporangia. I. fengii sp. nov. also differs from the hexaploid species I. japonica A. Braun, previously thought to be distributed in China and characterized by laevigate microspores.Because of their limited geographic range, small population size, low number of individuals, and disturbed habitats, I. fengii sp. nov. is evaluated as critically endangered(CR). To aid in the identification and conservation of these rare and endangered plants, we provide a key to all currently known quillworts in China.更多还原