Corethrogyne is a monotypic genus of flowering plant in the family Asteraceae (order Asterales), established by Swiss botanist Augustin Pyramus de Candolle in 1836. Its sole species, Corethrogyne filaginifolia, is known by the common names common sandaster and California aster.
The genus name derives from the Greek kórethron ("broom" or "brush") and gyné ("woman," "female"), a reference to the brush-like appendages on the flower's style branches. De Candolle originally described the type species as Corethrogyne californica; a name published earlier by William Jackson Hooker and George A. Walker Arnott in 1833, Aster filaginifolius, was later recognized as the same plant. Because botanical priority favors the older epithet, the species is now correctly called Corethrogyne filaginifolia. Over the twentieth century the plants were also grouped under the name Lessingia filaginifolia before being returned to Corethrogyne as a single, variable species carrying numerous synonyms. Plants of the World Online currently recognizes only this one species in the genus.
Corethrogyne filaginifolia is a robust perennial herb or subshrub, forming a simple to multibranched stem that can approach 1 meter in length or height. Its leaves are densely woolly, several centimeters long, and toothed or lobed near the base of the stem while becoming smaller higher up. Each stem branch bears either a single flower head or a cluster of several heads. The heads are wrapped in narrow, pointed phyllaries with purple tips that curl backward as the flower matures. Inside, purple, lavender, pink, or white ray florets surround a dense center of up to 120 tubular yellow disc florets. The fruit is a small achene topped with a pappus of reddish bristles that aids wind dispersal.
The genus is native to western North America, ranging from the southwestern corner of Oregon south through California to Baja California. Within that range it is a common component of a wide variety of plant communities — chaparral, woodlands, forests, scrub, grasslands, and even the specialized flora of serpentine soils.
Etymology
The genus name Corethrogyne, coined by de Candolle in 1836, comes from the Greek kórethron ("broom"/"brush") and gyné ("woman"/"female"), referring to the brush-like appendages on the style branches of the flower.
Distribution
Native to western North America, Corethrogyne filaginifolia ranges from southwestern Oregon through California to Baja California, where it commonly occurs across many plant communities.
Ecology
Corethrogyne filaginifolia grows as a common member of chaparral, woodlands, forests, scrub, and grassland communities, and it also tolerates the specialized serpentine-soils flora within its range.
Taxonomy Notes
Corethrogyne was established by Augustin Pyramus de Candolle in 1836 for the species he described as Corethrogyne californica. An earlier name, Aster filaginifolius (Hooker & Arnott, 1833), was later found to apply to the same plant; since it is the older epithet, the accepted name became Corethrogyne filaginifolia. The species was for a time classified under Lessingia filaginifolia before being restored to Corethrogyne. As of May 2024, Plants of the World Online treats the genus as monotypic, with C. filaginifolia its only accepted species — consistent with GBIF, which places the genus in family Asteraceae, order Asterales.
