The phyllaries are the most distinctive part of the flowerheads of grindelia squarrosa
, being thick, green, sticky, evenly spaced, circular in cross-section and (usually) curled back downwards. They are arranged in five or six rows. The all-yellow flowerheads have between 24 and 30 (occasionally fewer; sometimes zero) short ray florets surrounding a large center of disc florets (overall about 3/4 inch in diameter), which become elongated as they mature. The plant produces clusters of many flowerheads, branching towards the top of the stems.
The thick green leaves have small but prominent, regularly spaced teeth along the edges (closer together than the similar grindelia subalpina
), and clasp the stems at their base. Stems are hairless, off-white or pale reddish-brown in color.