The statistics of the number of family , genus and species of desert spermatophyte in gansu province .
甘肃省荒漠种子植物科,属,种统计。
In the part of seed plants , students should grasp various groups , key families , genera and their characters , distribution , phylogenic meaning and economic value , relationship among each group , and also should know the theory elements of the current spermatophyte systematics and their difference each other .