Camissoniopsis is a genus of flowering plants in the evening primrose family, Onagraceae, within the order Myrtales. Commonly known as suncups, the genus comprises around 14 accepted species and several infraspecific taxa. The plants are closely related to the genus Camissonia, from which they were segregated when a formerly broad circumscription of Camissonia — once containing up to 62 species — was divided among several closely related genera by W.L. Wagner and Hoch.
Like other members of Onagraceae, suncups bear four-petalled flowers that are typically yellow and cup-shaped, often opening at dawn. The genus is distinguished from Oenothera and Clarkia by its club- or head-shaped stigma rather than a four-lobed one. Species range from small annuals to perennial subshrubs, many growing in sandy, coastal, or disturbed habitats.
Camissoniopsis is centered on western North America, with the great majority of species endemic or near-endemic to the California Floristic Province — the coastal and inland ranges of California and adjacent Baja California. Notable species include Camissoniopsis cheiranthifolia (beach suncup), a coastal dune specialist, and Camissoniopsis micrantha, a widespread annual of sandy soils across California. With over 33,000 observations on iNaturalist, suncups are well documented by naturalists throughout the California region.
Etymology
The genus name Camissoniopsis means "resembling Camissonia," formed from Camissonia (itself named after the German botanist and poet Adelbert von Chamisso, 1781–1838) with the Greek suffix -opsis ("appearance" or "resemblance"), reflecting the genus's close morphological similarity to and historical inclusion within Camissonia.
Distribution
Camissoniopsis species are concentrated in the California Floristic Province — the coastal ranges, valleys, and adjacent Baja California of western North America. The related genus Camissonia, from which Camissoniopsis was split, is nearly entirely restricted to the same region, with one outlier in South America, suggesting the broader suncup clade is fundamentally a western North American group.
Taxonomy Notes
Camissoniopsis was established by W.L. Wagner and Hoch when the previously expansive genus Camissonia was split into several segregate genera, reducing Camissonia from up to 62 species to roughly 12. Both genera belong to the family Onagraceae (order Myrtales) and share the vernacular name "suncups." GBIF recognises Camissoniopsis as an accepted genus with 17 taxa including infraspecific names.
