''Pyrrocoma liatriformis'' 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 ...

. Its common names include Palouse goldenweed and smallhead goldenweed. It is native to the northwestern United States, where it is endemic to the Palouse prairie, growing in grassland dominated by blue bunchgrass. It is a perennial herb growing from a

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproot ...

, producing one to three stems up to 70 centimeters (28 inches) in length. The stems are erect and hairy. Leaves near the base of the plant are larger and rounder than the leaves connected to the stem, which are

lanceolate The following terms are used to describe leaf plant morphology, morphology in the description and taxonomy (biology), taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade ...

and hairy. Basal leaves measure 80–310 millimeters long and 9–30 millimeters wide, whereas cauline leaves measure 30–120 millimeters long and 5–20 millimeters wide. 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 ...

is four to five heads arranged in a

raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...

. Each head is composed of 17–25 yellow ray florets, each 6–14.5 millimeters in length, as well as 35–60 disc florets, each 7–11 millimeters in length. Originally known only from eastern Washington and adjacent northern Idaho, a joint survey by the

United States Forest Service The United States Forest Service (USFS) is an agency within the United States Department of Agriculture, U.S. Department of Agriculture. It administers the nation's 154 United States National Forest, national forests and 20 United States Natio ...

and the

Bureau of Land Management The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands, U.S. federal lands. Headquartered in Washington, D.C., the BLM oversees more than of land, or one ...

in 2011 confirmed the presence of ''P. liatriformis'' in extreme northeastern Oregon. The same survey also found another goldenweed species not previously found in Oregon, the similar ''P. scaberula'', which is native to Idaho grasslands in the Snake River Canyon. The species is classified by

NatureServe NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, United States, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and ...

as imperiled. Since much of the native Palouse prairie has been converted for agriculture, habitat loss is a primary factor threatening this species, along with competition from invasive weeds. It is not listed as endangered under the

Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...

References

External links

USDA Plants Profile
{{Taxonbar, from=Q15599517 liatriformis Flora of Idaho Flora of Washington (state) Flora of Oregon