CLARK, CURTIS* AND MARK FAULL. Biological Sciences, California State Polytechnic University, Pomona CA 91768, and Red Rock Canyon State Park, P.O. Box 26, Cantil CA 93519 . - Reevaluation of the Eschscholzia minutiflora autopolyploid complex (Papaveraceae).
The Eschscholzia minutiflora polyploid complex was thought to consist of three species, diploid E. parishii, tetraploid E. covillei, and hexaploid E. minutiflora. Although the latter two taxa show clear relationship (and are probably best treated as a single species), E. parishii differs from them in several respects, and will not hybridize with them. Recent work in the El Paso Mountains of the western Mojave Desert of California has revealed the actual diploid member of the series, consisting of plants that are morphologically indistinguishable from the tetraploid and hexaploid except by their larger flowers (the tetraploid has larger flowers than the hexaploid, as well). Whereas the tetraploid and hexaploid are sympatric over the entire range of the tetraploid, they occur with the diploid only in the El Paso Mountains. They are not found in mixed stands, but there is not a clear-cut habitat separation. The Eschscholzia minutiflora complex shows many similarities to classic autoploid complexes such as Ambrosia dumosa and Larrea divaricata; this supports the view that autoploidy has distinctive ecological consequences even if it is not genetically well-defined.