UW Burke Herbarium species comparison

Basal leaves lyrate and pinnatifid, up to 20 cm. long and 5 cm. wide;

cauline leaves smaller, becoming linear and entire upward.

Leaves alternate, the basal and lower cauline petiolate, becoming sessile upward;

leaf blades dotted with glands, oblanceolate to narrowly ovate, 10-30 cm. long, entire or shallowly dentate.

Heads several, broader toward the base;

involucre 10-15 mm. high, its middle and outer bracts spine-tipped, the larger spines 11-22 mm. long;

flowers yellow;

pappus of the outer flowers wanting, that of the others 3-5 mm. long;

receptacle densely bristly.

Heads borne singly, sessile, closely subtended by clusters of reduced leaves;

involucres ovoid to hemispheric, 25-35 mm. long, the involucral bracts glabrous, ovate to broadly lanceolate, pale green, with abruptly spreading appendages, brown, scarious, 1-2 cm. wide;

flowers many, yellow, the outer sterile corollas slightly longer than the central, fertile corollas;

pappus of flattened bristles 5-8 mm. long.

Achenes 7-8 mm. long.