Plagiobothrys collinus, commonly known as Cooper’s Popcornflower, is an annual herb that is native to grasslands and open areas in California and Oregon. It has a spreading or erect stem ranging from 10–40 centimeters (3.9–15.7 inches) in length. The plant is characterized by its inflorescence, which is a long, widely spaced series of tiny white flowers, each with a five-lobed white corolla no more than 7 millimeters wide, and sometimes as small as one millimeter. The bloom period for Cooper’s Popcornflower is from February through May, and the flowers are modest in showiness. The fruit is a minute nutlet with angular cross-ribs that are visible under magnification.

Cooper’s Popcornflower is valued for its drought tolerance and ability to thrive in poor soils, making it a suitable choice for wildflower meadows, restoration projects, and xeriscaping. It is often used to add texture and interest to naturalistic plantings. In cultivation, it requires full sun exposure and minimal water once established, preferring soils with fast drainage. While it is not commonly affected by diseases, its delicate appearance may be compromised by overwatering or rich soils.CC BY-SA 4.0