Dodecatheon pulchellum(Raf.) Merr. is a widespread and morphologically variable species of western North America. Analysis of morphological variation, combined with chromosome counts and evidence from a transplant study, showed this species to consist of two subspecies. Subspeciescusickiiis pubescent, mainly diploid, and occurs in the drier parts of the species range. The more variable ssp.pulchellumis glabrous to sparsely pubescent, mainly polyploid, and is widely distributed. Within ssp.pulchellum, three varieties can be recognized: the tall, many-flowered var.alaskanum, of wet, low-elevation habitats; the diminutive var.watsonii, generally of alpine habitats; and the intermediate and widely distributed var.pulchellum. Common garden studies indicate that size differences among these varieties have a genetic basis and that ecological differences exist inD.pulchellumeven among morphologically similar forms.Key words:Dodecatheon, Primulaceae, systematics, morphology, chromosome numbers, common garden studies.
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