''Potentilla rhypara'', also known as grimy mousetail and grimy ivesia, is a species of flowering plant in the

rose family Rosaceae (), the rose family, is a family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. The family includes herbs, shrubs, and trees. Most species are deciduous, but some ...

. It is native to

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

and

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

in the United States.''Ivesia rhypara''.
The Nature Conservancy.

Description

Potentilla rhypara is a perennial herb that grows from woody roots and a branching

caudex A caudex (: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is most ...

.''Ivesia rhypara''.
Nevada Natural Heritage Program. It has hairy, overlapping, compound basal leaves and stems up to 15 centimeters long. At the ends of the stems are clustered white or pale-yellow flowers. Blooming occurs in May through October.''Ivesia rhypara''.
Oregon Department of Agriculture.

Taxonomy

The species epithet ''rhypara'' ("grimy" in

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

) is derived from its dusty appearance and from its discoverer, James W. Grimes. There are two

varieties Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

of this plant. The var. ''rhypara'' grows on barren

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

and var. ''shellyi'' grows in rock cracks and crevices on

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ...

and tuff. When the plants grow in rock fissures they sometimes appear to be lined up in rows.''Ivesia rhypara'' var. ''rhypara''.
Center for Plant Conservation. Associated plants include ''

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, buckbrus ...

'', '' Poa sandbergii'', '' Gilia congesta'', '' Sitanion hystrix'', '' Scutellaria nana'', and ''

Eriophyllum lanatum ''Eriophyllum lanatum'', with the common names common woolly sunflower, Oregon sunshine and golden yarrow, is a common, widespread, North American plant in the family Asteraceae.Sierra Nevada Wildflowers, Karen Wiese, 2nd Ed. 2013, p. 116 Descri ...

''.

Threats

Threats to this species, particularly var. ''rhypara'', include

gold mining Gold mining is the extraction of gold by mining. Historically, mining gold from Alluvium, alluvial deposits used manual separation processes, such as gold panning. The expansion of gold mining to ores that are not on the surface has led to mor ...

, as the habitat contains gold deposits. Other threats include cattle,

off-road vehicle An off-road vehicle (ORV), also known as an off-highway vehicle (OHV), overland vehicle or adventure vehicle, is a type of transportation specifically engineered to navigate unpaved roads and surfaces. These include trails, forest roads, and ...

fire suppression Fire suppression may refer to: * Firefighting * Fire suppression systems * Wildfire suppression Wildfire suppression is a range of firefighting tactics used to suppress wildfires. Firefighting efforts depend on many factors such as the availabl ...

, and loss of pollinating insects.

References

{{Taxonbar, from=Q106909113, from2=Q6098823 rhypara Flora of Nevada Flora of Oregon Plants described in 1977