In many species of flowering plants, the floral meristem produces four distinct whorls of organs, each bearing certain characteristics specific only to that whorl. The typical flower will produce sepals, petals, stamens, and carpels in that order in position. Clarkia tembloriensis (Onagraceae) is an example of a plant whose wild-type phenotype follows the typical pattern of floral organ development. However, the crinkled petal mutant of C. tembloriensis is a homeotic mutant which produces abnormal hybrid organs in the second (petal) whorl. These abnormal organs bear anatomical and morphological characteristics of both sepals and petals. This study looks at the genetic basis for the phenotype of the sepaloid "crinkled petals" by using mRNA expression comparisons and probes from homologous genes in other species with sepaloid petals. Studies of crinkled petal and other similar mutants may give us insight into the development of organisms whose floral organ patterning can not yet be explained by current models.

Key words: Clarkia tembloriensis, crinkled petal, homeotic mutant, Onagraceae, sepaloid petals