Purshia tridentata

Purshia tridentata, with the common name bitterbrush,^[1][2][3] is a shrub in the genus Purshia of the family Rosaceae. It is native to mountainous areas of western North America.

Bitterbrush
Purshia tridentata, Wenas Wildlife Area
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Rosales
Family:	Rosaceae
Genus:	Purshia
Species:	P. tridentata
Binomial name
Purshia tridentata (Pursh) DC.
Synonyms[1]
Tigarea tridentata Pursh

Common names include antelope bitterbrush,^[3][2] antelope bush,^[2] buckbrush, quinine brush, and less commonly deerbrush, blackbrush, and greasewood.^[4] Some of these names are shared with other species.

Description

Purshia tridentata is a deciduous shrub growing to a height of 1–5 metres (3+1⁄2–16+1⁄2 feet). It has many branches and slender green,^[5] three- to five-lobed leaves 5–20 millimetres (1⁄4–3⁄4 in) long. It is a nitrogen-fixing plant.^[6]

The flowers are pale yellow,^[5] with five petals 6–8 mm long, and darker yellow anthers. The fruit is a cluster of dry, slender, leathery achenes each up to 1 centimetre (1⁄2 in) long.^[7]

• 
  Flowers
• 
  P. tridentata var. glandulosa on dry slope

Varieties

There are two named varieties of the species:

• Purshia tridentata var. glandulosa — Eastern Sierra Nevada, Southern California^[8]
• Purshia tridentata var. tridentata^[9]

Distribution

The plant is found from southeastern British Columbia in the north, east to Montana and Wyoming, south to New Mexico, and west in California.^[3] It grows on arid mountainsides and slopes, as well as rocky or drained soils with somewhat more moisture than the sagebrush steppe.^[5] It is often associated with Balsamorhiza as well as Wyethia species, and in southern areas hybridizes with Purshia stansburyana.^[5]

In California it occurs between 700–3,400 m (2,300–11,200 ft) above sea level, including in the Peninsular Ranges, Transverse Ranges, and Sierra Nevada, and southern Cascade Range.^[2][10] Further north it occurs at lower elevations, such as at 320–1,065 m (1,050–3,494 ft) in British Columbia.^[11]

Ecology

The shrub is an important forage plant for many game animals, including deer,^[5] especially during the winter.^[12]