Calochortus (Liliaceae) is a large genus (75 spp.) of bulbous herbs with flowers of kaleidoscopic variety and exquisite complexity. It has a center of diversity in California and ranges north to British Columbia, west to the Dakotas, and south to Mexico and Guatemala. Calochortus has undergone striking radiations in flower morphology, habitat, and substrate preference, and most taxa have narrow ranges. Floral syndromes include Mariposas with large, brightly colored, tulip-like blossoms with an erect perianth (tepals); Cat’s Ears with a smaller, spreading perianth densely covered with trichomes; Star Tulips with spreading, mostly glabrous tepals; and Fairy Lanterns with closed, globular nodding flowers. Calochortus petals are marked by unique, often brightly colored glands. Species inhabit deserts, grasslands, chaparral, meadows, vernal pools, springs, montane woodlands, and forest understories. One quarter of all species occur on or are limited to serpentine; nearly as many are federally endangered or extinct. Several species are visited by a wide range of pollinators, while others attract a narrow range of visitors.
Given the diversity of habitats, geographic ranges, and floral forms seen in Calochortus, a well-resolved and densely sampled phylogeny would provide the opportunity to address many questions at the interface of ecology, evolution, and biogeography: Are species with similar floral syndromes each other’s closest relatives, or have such syndromes arisen multiple times independently? What is the adaptive significance and developmental origin of each floral syndrome? Has the ability to tolerate serpentine evolved more than once within and among clades? What has been the historical pattern of geographic spread within the genus? Do closely related species occupy similar ecological distributions?
We are collaborating with Dr. Tom Givnish (University of Wisconsin, Madison) to develop a phylogeny for Calochortus and to investigate gene flow and diversification in floral form among various species native to California and Mexico.