Tetradymia axillaris is a flowering plant in the daisy family known by the common names longspine horsebrush[1] and cottonthorn.

The plant forms a sprawling thicket and is very spiny.

When in foliage the bush has green, hairy stems and bears yellow daisylike flowerheads in the axils, or angles, of the newest branches.

The fruits are released in masses of cottony seed.

[2] The sharp spines were used as tattooing needles by the Kawaiisu Native Americans of California.