A study of the genus Dodecatheon has been made with two purposes in view: 1. A reclassification, of the genus in northwestern America, including Alaska, Yukon, British Columbia, Alberta, Saskatchewan, Washington, Oregon, Idaho and Montana. 2. An incidental survey of its horticultural possibilities. The method of approach has included collection of living material, hybridization, cytological study, and examination of seven to eight hundred herbarium specimens. Throughout the progress of this work, a number of horticulturally valuable characteristics have been observed and noted. Chromosome counts have been obtained for a number of species and from a number of localities. These counts indicate an interesting pattern of polyploidy within the genus: diploids on the east of the Cascade Mountains, polyploids extending north to Alaska along the Pacific Coast. Similarity of diploids and polyploids suggest autoploidy. As a result of the work outlined above, the genus has been reclassified into ten species and one variety on the basis of morphology, cytology, and distribution. Though a number of these species, two particularly, are variable, further subdivision is considered unwise until much more can be learned about the cytogenetics of the genus. Finally, the suggestion is made that cytogenetic study is the next step in horticultural improvement and might provide valuable evidence regarding the course of evolution in the genus. / Science, Faculty of / Botany, Department of / Graduate