中国水韭属两个四倍体新种 postprint

Abstract: Two new tetraploids quillworts species, Iso雝es longpingii and I. xiangfei, from China are described and illustrated. I. longpingii is a fully submerged plant found in a small pond of Hunan Province. It is morphologically similar to I. sinensis, but differs in its small and tuberculate-cristate megaspores and soft slender leaves that grow up to 60 cm. It is also similar to hexaploid I. orientalis, but differs in its 44 chromosomes and tuberculate-cristate megaspores. I. xiangfei is most similar to diploid I. yunguiensis in megaspore ornamentation, but differs in its microspore ornamentation, oblong sporangium, and 44 chromosomes. There are a few individuals of I. longpingii found in Ningxiang County of Hunan Province, and I. xiangfei is distributed in the wetlands of Tongdao and Huitong counties of Hunan Province. Because of their limited geographic range, small populations, fewer individuals and disturbed habitats, I. longpingii and I. xiangfei are ecaluated as critically endangered (CR) and vulnerable (VU) category, respectively, according to the IUCN Red List criteria. A key to all the current known Chinese quillworts is also provided for further taxonomic identification and conservation of these rare and endangered plants in China.