中文摘要：

统万城位于陕西省榆林市靖边县无定河畔，北与内蒙古鄂尔多斯市的乌审旗相毗邻。通过对统万城遗址土夯城墙上苔藓植物的分布、植物多样性、水分生态类型及区系地理成分分析，得出以下结论：（1）统万城遗址土夯城墙上苔藓植物苔藓植物共有26种，其中苔纲1科1属1种，藓纲2科9属25种；（2）苔藓植物在城墙阴阳面种类分布有所不同，城墙阳面苔藓植物共有18种，占苔藓植物总数的69．23％，呈斑块状分布，多数为旱生种类。城墙阴面苔藓植物共有24种，占苔藓植物总数的92．31％；（3）不同生境苔藓植物物种多样性变化体现为城墙阴面下部苔藓植物的物种多样性指数最高，城墙阳面中上部苔藓植物的物种多样性指数最低；（4）水分生态型分析表明：旱生类型占总种数的73．07％，中生类型占26．92％，不存在湿生和湿中生类型；（5）统万城遗址城墙上的苔藓植物共有6种区系地理成分，其中北温带分布最多，共14种，占总种数的53．84％，古热带和温带亚洲分布最少，各有1种，各占总种数3．85％。

英文摘要：

Tongwan Castle Site located in Shaanxi Province, the northernmost of Wuding River, adjacent to the north Inner Wushenqi. Bryophytes were collected on Tongwan Castle ruins rammed earth walls. These bryophytes were identificated and analyzed to draw the following conclusions： （ 1 ） There are 26 kinds of moss collected, among them only one family 1 genera and 1 species belonging to Marchantiophy- ta ;two families,9 genera and 25 species belonging to bryopsida. （2）According to different habitats bryo- phytes show that there were 18 kinds of bryophytes in the sunny side walls ,69.23% of the total species of bryophytes, and they were patchy distribution and all were xeric species ： There were 24 kinds of bryopsida in the night side walls ,92.31% of the total species of bryophytes ,but has a different distribution pattern changes. （3）Through the study of Tongwan castle ruins rammed earth walls bryophytes species diversity show that the highest species richness of bryophytes in the lower part of the wall, the least species richness of bryophytes in the upper part of the wall, the moderate species richness of bryophtes in the other part of the wall. （4）26 bryophytes water ecotypes showed that a total of 73.07% belongs to the type of xeric, a total of 26.92% belongs to the type of mesogenous, aquatic and medium aquatic type does not exist. From this, blyophytes species of the Tongwan castle rammed earth walls of the ruins closely related to the physi- cal properties of the soil environment and soil moisture. （5） 26 kinds of bryophytes that were studied by floristic analysis methods showed that there were six kinds of floristic composition. Among them, the most is the north temperate elements,a total of twelve kinds, accounting for 53.84% of the total, at least types of Pantropical elements and Temperate Asian elements,each containing one kind,3.85% of the total.