Purshia
Read about Purshia in the Standard Cyclopedia of Horticulture
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Purshia (after F. T. Pursh, or Pursch, as is the original spelling of his name, 1774-1820; born at Grossenhain, in Saxony; traveled in this country and wrote a flora of North America). Syn., Kunzia. Rosaceae. Low deciduous spreading shrub, allied to Cercocarpus, with alternate, mostly fascicled, small, cuneate and tridentate lvs.: fls. solitary, yellowish; calyx-tube tubular; petals spatulate, 5; stamens numerous; pistils 1 or sometimes 2: fr. a pubescent leathery achene exceeding the persistent calyx. Of little ornamental value with its sparse grayish or bluish green foliage and its rather inconspicuous fls. and frs., and but rarely cult. Probably hardy as far north as Mass., requiring sunny position and well-drained soil; an excess of moisture, especially during the winter, proves fatal to it. Prop. by seeds and probably by layers. The only species is P. tridentata, DC. (Kunzia tridentata, Spreng.). Diffusely branched shrub, attaining 5, rarely 10 ft.: lvs. cuneate-obovate, 3-lobed at the apex, whitish pubescent beneath, 1/4-3/4in. long: fls. solitary on short branchlets, almost sessile, yellowish, about 3/4in. across: fr. ovate-oblong, acuminate. April-July. Ore. to Wyo., New Mex. and Calif. B.R. 1446. Var. glandulosa, Jones (P. glandulosa, Curran), is glandular and has very small, almost glabrous lvs., sometimes pinnately 5-lobed. Alfred Rehder.
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Purshia (bitterbrush or cliff-rose) is a small genus of 5-8 species of flowering plants in the family Rosaceae, native to western North America, where they grow in dry climates from southeast British Columbia in Canada south throughout the western United States to northern Mexico.
They are deciduous or evergreen shrubs, typically reaching 0.3-5 m tall. The leaves are small, 1-3 cm long, deeply three- to five-lobed, with revolute margins. The flowers are 1-2 cm diameter, with five white to pale yellow or pink petals and yellow stamens. The fruit is a cluster of dry, slender, leathery achenes 2-6 cm long.
The evergreen species were treated separately in the genus Cowania in the past; this genus is still accepted by some botanists.
- Species
- Purshia ericifolia - Heath Cliffrose. Texas.
- Purshia glandulosa - Desert Bitterbrush. Nevada, Utah, Arizona.
- Purshia mexicana - Mexican Cliffrose (syn. Cowania mexicana). Mexico, Arizona.
- Purshia pinkavae - Pinkava's Cliffrose. Arizona.
- Purshia plicata - Antelope Bush (syn. Cowania plicata). Mexico (Nuevo León).
- Purshia stansburiana - Stansbury Cliffrose (syn. P. mexicana var. stansburiana, Cowania stansburiana). Idaho south to California, Arizona and New Mexico.
- Purshia subintegra (possibly a hybrid between P. pinkavae and P. stansburiana). Arizona.
- Purshia tridentata - Antelope Bitterbrush. British Columbia south to California and New Mexico.
The classification of Purshia within the Rosaceae is presently unclear. The genus was originally placed in the subfamily Rosoideae, and later in subfamily Dryadeae along with the genera Cercocarpus, Chamaebatia and Dryas, all genera sharing root nodules that host the nitrogen-fixing bacterium Frankia. However, recent genetic research indicates that Dryadeae may be polyphyletic, with Dryas not closely related to the other genera.
P. tridentata, Lava Beds National Monument
P. tridentata, Red Rock Canyon, Nevada
External links
- Jepson Flora Project: Purshia (click 'next taxon' to see species accounts of Californian species)
- USDA Plants Profile: Purshia
- Germplasm Resources Information Network: Purshia
- Phylogeny of Rosoideae (pdf file)