XVI International Botanical Congess

D. luteum is a California state-listed rare species, restricted to two populations. Using allozyme and RAPD analyses, the level and patterns of variation were determined for three populations, one wild and two cultivated, and compared to diversity in a widespread congener, D. nudicaule. The wild population had the highest level of polymorphism for both markers, and had similar levels of diversity to D. nudicaule. However, both cultivated populations had unique markers, making them important sources of variation for future management of the species. Allozymes, RAPDs, and DNA sequences were used to test the hypothesis of hybrid origin of D. luteum from D. decorum x D. nudicaule proposed on the basis of studies of morphology, chemistry, and ecology. Our data do not support the hypothesis of recent hybrid origin of D. luteum.