''Purshia'' (bitterbrush or cliff-rose) is a small

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of 5–8 species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s in the family

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are '' Alchemilla'' (270), ''Sorb ...

which are native to western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

Description

''Purshia'' species form

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

s, typically reaching tall. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

are long, deeply three- to five-lobed, with revolute margins. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s are 1–2 cm in diameter, with five white to pale yellow or pink petals and yellow stamens. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

is a cluster of dry, slender, leathery

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not o ...

s which are 2–6 cm long. The roots have nodules that host nitrogen-fixing '' Frankia'' bacterium.

Taxonomy

Taxonomic history

The genus was originally placed in the subfamily

Rosoideae The rose subfamily Rosoideae consists of more than 850 species, including many shrubs, perennial herbs, and fruit plants such as strawberries and brambles. Only a few are annual herbs. The circumscription of the Rosoideae is still not wholly ce ...

. In the past, the

species were treated separately in the genus ''Cowania''; this genus is still accepted by some botanists.

Modern classification

The classification of ''Purshia'' within the family

has been unclear. It is now placed in the subfamily Dryadoideae.

Species

''Purshia'' comprises the following species: * '' Purshia ericifolia'' (Torr. ex A.Gray) Henr. – Heath cliffrose (Texas) * '' Purshia glandulosa'' Curran – Desert bitterbrush (Nevada, Utah, Arizona) * '' Purshia mexicana'' (D.Don) Henr. – Mexican cliffrose (Mexico, Arizona) * '' Purshia pinkavae'' Schaack – Pinkava's cliffrose (Arizona) * '' Purshia plicata'' (D.Don) Henrard (syn. ''Cowania plicata'') – Antelope bush (Nuevo León, Mexico). * '' Purshia stansburyana'' (Torr.) Henr. – Stansbury cliffrose (Idaho south to California, Arizona and New Mexico) * ''

Purshia tridentata ''Purshia tridentata'', with the common name bitterbrush, is a shrub in the genus ''Purshia'' of the family Rosaceae. It is native to mountainous areas of western North America. Common names include antelope bitterbrush, antelope bush, buckb ...

'' (Pursh) DC. – Antelope bitterbrush (British Columbia south to California and New Mexico)

Hybrids

The following hybrid has been described: * ''Purshia'' × ''subintegra'' (Kearney) Henr. (''P. pinkavae'' × ''P. stansburyana'') – (Arizona)

Species names with uncertain taxonomic status

The status of the following species and hybrids is unresolved: * ''Purshia ciliata'' Dennst. * ''Purshia mollis'' Lehm. * ''Purshia plicata'' (D.Don) Henr. * ''Purshia subintegra'' (Kearney) Henrickson

Distribution and habitat

The genus is native to western

, where the species grow in dry climates from southeast

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

, south throughout the

western United States The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the We ...

to northern Mexico.

Gallery

Purshia_tridentata_8234.jpg, ''P. tridentata'',

Lava Beds National Monument Lava Beds National Monument is located in northeastern California, in Siskiyou and Modoc counties. The monument lies on the northeastern flank of Medicine Lake Volcano and has the largest total area covered by a volcano in the Cascade Range. ...

Purshia stansburiana 1.jpg, ''P. stansburiana'', Red Rock Canyon, Nevada Purshia stansburiana 4.jpg, ''P. stansburiana'', Red Rock Canyon, Nevada

References

External links

*
Jepson Flora Project: ''Purshia''
— ''(click 'taxon' to see treatments of California native species)'' Rosaceae genera {{rosaceae-stub