Romneya trichocalyx, the bristly Matilija poppy or hairy Matilija poppy, is a species of flowering plant in the poppy family. This poppy is native to San Diego, Ventura, and Santa Barbara counties in California, as well as and Baja California, Mexico, where it grows in dry canyons in chaparral and coastal sage scrub plant communities. Like its relative Romneya coulteri, it is used as an ornamental plant, kept for its large, showy flowers. It is named after Irish astronomer John Thomas Romney Robinson.