Several morphotypes of simple inflorescences occurring in the genus Spiraea L. (Rosaceae), widely used for classification and determination, but not uniformly interpreted in the literature, are correctly defined. Taxonomically, S. compsophylla Hand.-Mazz. is synonymized with the imperfectly known S. calcicola W. W. Sm., whose amplified description and illustration are added. A newly distinguished species, hitherto confused with the former name, is described from Yunnan Province in China and illustrated as S. adiantoides Businský, with its assignment to section Glomeratae Nakai. Two imperfectly known and confused species of Spiraea sect. Chamaedryon Ser. from Taiwan, S. tarokoensis Hayata and S. tatakaensis I. S. Chen, are carefully described, illustrated, and compared with six similar Chinese species. A new variety, S. lasiocarpa var. villosa Businský, is described from western Sichuan Province, accepting the concept that S. lasiocarpa Kar. & Kir., described from today's eastern Kazakhstan and hitherto neglected in Chinese floras, is the correct name for the Chinese taxon S. mongolica Maxim. Two imperfectly known taxa from southwestern Sichuan, S. muliensis T. T. Yu & L. T. Lu and S. daochengensis L. T. Lu, were found to be conspecific after comparison of their respective holotypes and a newly found population; the former is accepted as the correct name. Spiraea sericea Turcz. is accepted only at the rank of the variety as S. media Schmidt var. sericea (Turcz.) Maxim. A key to the Chinese species of Spiraea with simple inflorescences is newly compiled, encompassing 40 species.