Chamise, or Greasewood, (Adenostoma fasciculatum), a member of the Rose family, is a flowering plant native to California and northern Baja California. This shrub is one of the most widespread plants of the chaparral biome, sometimes forming monotypic stands.

Chamise is an evergreen shrub with dry-looking stick-like branches. The leaves are quite small, sprouting in clusters from the branches. Its leaves are shiny with flammable oils, especially in warmer weather. Chamise is said to be highly flammable but can be more fire-resistant with occasional watering. The branches terminate in bunches of white tubular flowers.

Chamise is one of the best plants for anchoring a slope and resisting erosion, due to its wide-spreading and deeply-penetrating roots. In maturity, it develops a large burl from which it will resprout after fire or severe pruning. In the wild, it is the host plant of a common root parasite, Chaparral Broomrape.

There are three recognized varieties of this plant. Adenostoma fasciculatum var. fasciculatum is found throughout the range of the species. Adenostoma fasciculatum var. obtusifolium is found only in San Diego and Orange Counties. Adenostoma fasciculatum var. prostratum, a low-growing form, is found primarily on the northern Channel Islands. A cultivar known as 'Black Diamond' (Adenostoma fasciculatum 'Black Diamond') is popular and widely available.