Githopsis diffusa

Abstract: Githopsis comprises four species of annuals usually associated with oak woodland and distributed in western North America from northern Baja California Norte to southern British Columbia. Chromosome numbers of Githopsis are based on 10, a base number not found elsewhere in western North American Campanulaceae. Breeding systems in Githopsis range from obligately allogamous to primarily autogamous. Autogamy is mediated by late invagination of stylar hairs or deposition of pollen on the stigmatic surface before anthesis. Reduction in flower size, narrowness of filament base, and reduction in extent of stylar papillae are character state changes associated with the shift to autogamy. Githopsis pulchella grows in xeric sites in the foothills of northern Sierra Nevada and southern Cascade Range of California. It is obligately outcrossed, diploid (n = 10), and here divided into three subspecies. Githopsis specularioides grows in xeric sites from northern San Luis Obispo and Kern counties, California, north to southern British Columbia. It is facultatively autogamous and tetraploid (n = 19, 20). I propose that G. specularioides is a derivative of G. pulchella. Githopsis diffusa grows in mesic sites in California and Baja California Norte in the coastal mountain ranges and east to the southern part of the Cascade Range. It is primarily autogamous and comprises three diploid (n = 10) and one tetraploid (n = 20) subspecies. Githopsis tenella is diploid (n = 9), primarily cleistogamous, and occurs in mesic areas in the Greenhorn and Tehachapi Mountains of Kern and Tulare counties, California. Four other new taxa are described here: Githopsis pulchella subsp. campestris, G. pulchella subsp. serpentinicola, G. diffusa subsp. robusta, and G. diffusa var. guadalupensis; and four new combinations are made: G. diffusa subsp. filicaulis, G. diffusa subsp. candida, G. diffusa var. candida, and G. pulchella var. glabra.