灰藓科分类与系统发育研究

Hypnaceae, belonging to pleurocarpous mosses, includes 52 genera, ca. 590 species in the world. The family widely occurs in the world exception of Antarctic. The family Hypnaceae has a complex history during which it has undergone much change in the morden concept, and has become even more puzzling since our very limited knownledge of it. Definining the relationship among genera and circumscribing the family as a natural monophyletic taxon is a major challenge for bryologists. Firstly, this family is very heterogeneous and may be not a monophyletic group. Secondly, the taxonomic revision work on Hypnaceae is very few, especially for some genera e.g. Ectropothecium, Vesicularia, Glossadelphus, Taxiphyllum. Thirdly, systematic position of some genera need further be confirmed with more data. Forthly, some morphological characters, such as, pseudoparaphyllia, axillary hairs, peristome, cross section of stem and inner perichaetial leaves have not been comprehensively studied yet in Hypnaceae. Ectropothecium, Glossadelphus, Vesicularia and Taxiphyllum will be taxonomically revisied in this project. Some morphological characters, e.g. pseudoparaphyllia, axillary hair, section cross of stem and inner perichaetial leaves will be further studied and re-evaluated for taxonomic value in this family. Based on the morphological and molecular data, the relationships among genera will be further clarified in this project. We also will present further study for the phylogeny reconstrction by increasing genes and samples within Hynaceae and its related ones, and clarify the phylogenetic relationship with Pyalsiadelphaceae, Sematophyllaceae, Amblystegiaceae, and divergence time among these familes, which were not recognized previously in systematics based only on morphology.

灰藓科是侧蒴藓类植物中的一个大科，全世界现有52属，约590种，分布于除南极以外世界各地。灰藓科是一个研究较少，分类学上问题较多的类群。首先，它是单系还是多系并不十分清楚。其次，分类学修订工作非常薄弱，尤其是一些种类较多的大属更是如此。第三，后来新建的属其系统位置仍然需要更多的数据来确认。第四，一些形态性状，如假鳞毛、腋毛、蒴齿、孢子等需要继续观察和研究。本研究将对灰藓科中偏蒴藓属、明叶藓属、扁锦藓属、鳞叶藓属等开展世界性分类学修订工作。并且对一些性状特征，如：假鳞毛、腋毛、茎横切面和内雌苞叶进行全面观察和分类学价值重新评价。此外，通过形态和分子的手段对灰藓科开展系统发育研究，并对一些属的系统位置进行探讨。通过选取更多的基因片断和增加取样对灰藓科与毛锦藓科、锦藓科、柳叶藓科等类群的系统关系以及它们分化的时间进行深入的分析和研究。

灰藓科是分类学上非常困难的类群。本项目拟通过分类学研究厘清该科的一些种类，并对某些属的定义给予重新评价。.本项研究主要是通过文献整理和模式、普通标本观察等手段开展分类学修订工作。我们重点对鳞叶藓属和叶齿藓属进行分类学研究。以下是我们对两个属开展工作的具体成果。.一、鳞叶藓属.1. 属的定义：.我们认为鳞叶藓属植物的重要特征为：雌雄异株；无专门的无性繁殖结构；带叶的茎和枝通常扁平而开展，或略呈圆柱状；芽原基在茎和枝上间隔分布，数量多；芽原基及枝条基部具有明显的叶状或三角状假鳞毛；中轴略分化；茎叶和枝叶同形，叶缘几乎全具细锯齿；中肋2，短，偶尔不明显；叶细胞平滑，中部细胞狭长，长宽比常在10:1以上，角部细胞明显较中部细胞短，方形至矩形。.2. 分类学处理：.确认了鳞叶藓属10个物种；2个新组合名称；6个种被处理为其他种类的异名:.二、扁锦藓属和叶齿藓属：.我们逐一核查了扁锦藓属（90个物种名称）和叶齿藓属（14个物种名称）所有的合格发表名称（104个），检查了相应物种的标本，同时观察了与之易混淆类群的标本，例如，偏蒴藓属、鳞叶藓属、麻锦藓属、刺果藓属等属的部分物种的标本。我们共检查了368号标本，其中模式标本158号，并且对叶齿藓属进行了首次世界性分类学修订。我们的主要研究结果如下：.1. 叶齿藓属是一个自然类群，归属于刺果藓科。.2. 叶齿藓属植物的植株外观、叶形、叶细胞疣的类型、叶边齿的类型、叶片角部细胞特征、芽原基及假鳞毛类型和蒴齿形态等性状对于属的界定具有重要参考价值；叶细胞疣的类型、茎中轴是否分化、叶片大小及长宽比、繁育系统以及蒴柄是否平滑等特征对于该属物种的界定十分重要。.3. 叶齿藓属全世界共有9种。.4. 本研究处理了14个名称的归属。其中，9个新组合名称；3个物种名称被处理为其他属物种的新异名；2个物种恢复了以前的归属；另外，2个有争议的物种归属被确认。