Pyrrocoma liatriformis is a species of flowering plant in the family Asteraceae. 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, 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 and hairy. Basal leaves measure 80âÂÂ310 millimeters long and 9âÂÂ30 millimeters wide, whereas cauline leaves measure 30âÂÂ120 millimeters long and 5âÂÂ20 millimeters wide. The inflorescence is four to five heads arranged in a raceme. Each head is composed of 17âÂÂ25 yellow ray florets, each 6âÂÂ14.5 millimeters in length, as well as 35âÂÂ60 disc florets, each 7âÂÂ11 millimeters in length.
Originally known only from eastern Washington and adjacent northern Idaho, a joint survey by the United States Forest Service and the Bureau of Land Management 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 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.