Dodecahema leptoceras

About

Dodecahema is a genus of plants in the family Polygonaceae with a single species restricted to California, where it is an endangered species on the state and federal levels. Its common name is slender-horned spineflower. This is a small annual plant forming a patch of spreading basal leaves a few centimeters in diameter, or slightly larger when more moisture is available. It bolts an erect stalk upon which it bears inflorescences of flowers. Each group of white or pink flowers is enclosed in a tiny cup of fused bracts which is only a few millimeters wide. The fruit is a dark achene about 2 millimeters long.

Summary from Wikipedia