Calycadenia oppositifolia is a species of flowering plant in the family Asteraceae known by the common name Butte County western rosinweed. It is native primarily to Butte County, California, although a few populations have been found in other parts of the state.[1] It grows in the foothills of the high mountain ranges.
Calycadenia oppositifolia is an annual herb producing an erect, unbranching, hairy stem approaching 30 centimeters (12 inches) in maximum height. The leaves are linear in shape and up to 5 centimeters (2 inches) long, arranged oppositely about the stem. The inflorescence bears bracts coated in large resin glands and dense clusters of flower heads. The hairy, glandular flower head has a center of several disc florets surrounded by a few white or reddish triple-lobed ray florets. Each ray floret has three lobes at the tip, the middle lobe being shortest. The fruit is an achene; those developing from the disc florets have a pappus of scales.[2]