CHROMOSOME N UMBER, behavior, and morphology are some of the natural indexes to the phylogeny of a group of organisms. Consequently, as a result of developments in the field of cytology, rather frequent attempts have been made in recent years to analyze on a chromosomal, basis the taxonomic status and affinities of certain plants. Often the results of those attempts have supported conclusions already reached by systematists; in other cases no such agreement has been found, and different interpretations have been suggested. In 1933 a chromosomal survey of Sedum was initiated as a beginning of such an analysis of the Crassulaceae, for only a system built on entirely new (embryologic?) foundations will perhaps have a chance of producing a more acceptable systematization within this family than the Linnean (Froderstr6m, 1929). An introductory paper on Sedum (Baldwin, 1935), a study of polyploidy in Sedum ternatumn Michx. (Baldwin, 1936), and a report on chromosome numbers in Crmssula (Baldwin, in press) have been written as parts of this analysis of the family. The cyto-taxonomy of section Telephium of intergrading forms that to determine the limits of a species becomes very difficult. The taxonomy of this group therefore presents numerous problems in synonymy and degree of specific rank. To illustrate, a s:ngle example, perhaps of the most confused condition in the section, will be cited. According to the Index Kewensis, 25 species of Anacampseros and 34 species of Sedumn are reduced to S. Telephium, and similarly 20 species of Anacampseros and 6 species of Sedum are reduced to S. maximum. And, according to Fr6derstr6m (1929), whom Praeger (1932) considers the iauthor of the best study as yet produced on the genus, S. maximum is one of seven subspecies of S. Telephium. Material for study was taken from plants growing in the Sedum collection at The Blandy Experimental Farm, Boyce, Virginia. Specimens of the species herein discussed, as well as of other species investigated, will be deposited in the Bailey Hortorium, Cornell University. Crystal violet preparations were made of root tips fixed in Nawaschin's solution and sectioned at 7-13 microns. Aceto-carmine smears were made of anthers and root tips subsequent to