Comparative Morphology of Schistidium lancifolium and its Relevant Species

Schistidium lancifolium is commonly confused with S. apocarpum and S. strictum because of the similarity in morphological characteristics and geographic distributions in the Henlan Mountains of Inner Mongolia and Wudalianchi in Heilongjiang. In this study, optical microscopy combined with related references (e.g.Blom's morphology and Ignatova's molecular phylogeny of taxonomy) were used to identify the collections from the two regions, and detailed comparisons of the morphological characters of three species are given below. These species were well delimited, and their morphological characteristics were: costa distantly smooth or with scattered low papillae near apex, upper leaf margins finely denticulate or smooth, hair-points finely spinulose-denticulate but often smooth in the upper part in S. apocarpum; costa strongly dorsally convex and distantly papillose in upper 1/2 of leaf length with papillae increasing in height towards the leaf apex, upper leaf margins strongly and irregularly dentate to serrate, hair-point sharply and strongly spinulose-denticulate in S. lancifolium; costa distant and lamina cells with papillae in S. strictum. Illustrations of the three species and a key to all Schistidium species in China are provided. Not only did this research confirm the existence and geographic distributions of S. lancifolium in China, but also enriched overall Schistidium data.