''Sericocarpus rigidus'' is a species of flowering plant in the family

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

known by the common name Columbian whitetop aster. It is native to the

Pacific Northwest The Pacific Northwest (PNW; ) is a geographic region in Western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though no official boundary exists, the most common ...

of North America, where it is known from southern

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

south along the coast to

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

and

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 ...

.''Sericocarpus rigidus''.
The Nature Conservancy.''Sericocarpus rigidus''.
Center for Plant Conservation. This

rhizomatous In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

perennial herb grows up to about 37 centimeters tall. Leaves along the stem are somewhat oval in shape and up to 6 centimeters long. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

has clusters of

flower heads A pseudanthium (; : pseudanthia) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers ...

each up to about a centimeter long. Each contains white or off-white disc florets and usually a few white ray florets.''Sericocarpus rigidus''.
Flora of North America.''Sericocarpus rigidus''.
Washington Burke Museum. This species grows in

grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

habitat which is generally dominated by

Idaho fescue ''Festuca idahoensis'' is a species of grass known by the common names Idaho fescue and blue bunchgrass. It is native to western North America, where it is widespread and common. It can be found in many ecosystems, from shady forests to open plai ...

(''Festuca idahoensis''). It grows in gravelly soils originating from

glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

activity in the northern part of its range, and clay soils farther south. The soils are moist most of the year but dry in the summer. Associated species include

snowberry ''Symphoricarpos'' is a small genus of about 15 species of deciduous shrubs in the family Caprifoliaceae. With the exception of the Chinese coralberry, ''Symphoricarpos sinensis, S. sinensis'', which is indigenous to western China, all species a ...

(''Symphoricarpos albus''),

serviceberry ''Amelanchier'' ( ), also known as shadbush, shadwood or shadblow, serviceberry or sarvisberry (or just sarvis), juneberry, saskatoon, sugarplum, wild-plum or chuckley pear,A Digital Flora of Newfoundland and Labrador Vascular Plants/ref> is a ...

(''Amelanchier alnifolia''), Oregon sunshine (''Eriophyllum lanatum'') and early blue violet (''Viola adunca''). Much of the habitat is also covered with

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

such as Scot's broom (''Cytisus scoparius'') and yellow hairgrass (''Aira praecox''). The invasion of the habitat by introduced species is a threat to this plant. Other threats include loss of habitat to development, off-road vehicles, military activity, 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 ...

References

{{Taxonbar, from=Q7454736 Astereae Flora of British Columbia Flora of Oregon Flora of Washington (state)