Abstract: Seeds from 28 plant species belonging to the Poaceae, Chenopodiaceae, Fabaceae, Asteraceae, Polygonaceae, Rosaceae, Lamiaceae, Alliaceae, Caryophyllaceae, Zygophyllaceae and Amaranthaceae, which are the main plant families present in the four grassland types on the north slope of Tianshan (regional indication would be good, eg. Northwest China), were collected, and their morphological characters recorded and germinability before and after sheep-rumen-passage determined. The seeds of the 28 plant species showed rich diversity in morphological characteristics, and their weights spanned a wide range, with the heaviest being 22 times the weight of the lightest. Similarly for dimensions of length, width and height, and the maxima and minima of the various species differed by a factor of 14, 24, and 22, respectively. A shape index indicated that in most species seeds were either markedly flattened or approximately sphericalin shape. For most species seed morphology was modified by adjacent structures, such as an awnon an adhering lemma in the Poacea, or fruiting wings in some herbs. Some seeds were borne in mucilaginous structures. Morphological characteristics of Poaceae, Chenopodiaceae and Fabacea were taxonomically diagnostic. Seeds of the remaining families did not show any phylogentic consistency in their morphological characteristics. The water absorption of plant seeds during germination can be divided into three stages: a fast water absorption phase, a slow water absorption phase and constant water content phase. The germination rate of legume seeds was very low, ranging from 4.2%-15.0%, while germination rate of Asteraceae species was up to 97%; the germination rate of 6 Chenopodiaceae species ranged from 41%-97%, and of 10 Poaceae species ranged from 53%-99%. After sheep-rumen-passage, the germination rate of Fabaceae seeds was increased, whereas the germinability of seeds of other families was decreased. However, despite reduced germinability after rumen passage, because of the survival of some seeds sheep browsing provides a possible pathway for seed dispersal. The germination rate of seed before rumen digestion was significantly associated with shape index and seed weight, while it was significantly correlated with seed shape index and seed length after rumen digestion. Additionally, there was convergence in germination behavior before and after digestion among seeds that have a close genetic relationship.