Perennials 18-46(-65) cm; taprooted, sometimes spreading by rhizomes, forming additional clumps. Stems 1-50+, ascending to erect (sometimes brown, or reddish to dark brown, often proximally brittle), often short-branched in distal ¹ / 2 , sparsely to densely long-hispid and strigose (hairs often broken off, especially proximally), sometimes becoming moderately hairy and densely stipitate-glandular distally (axillary fascicles of leaves often present). Leaves generally ascending, congested; proximal cauline petiolate, blades linear-oblanceolate, (15-)24-42 × (2-)3-6(-8.5) mm, bases cuneate to attenuate, margins flat, entire, strigoso-ciliate, proximally long-hispido-strigose, apices acute, faces sparsely to moderately hispido-strigose and sparsely to moderately stipitate-glandular, or moderately to densely hispido-strigose and eglandular; distal sessile (bright green to grayish green), blades linear-oblanceolate to narrowly oblanceolate (rarely broader), (9-)16.5-30 × (1.5-)2.2-4.3(-6) mm, usually little reduced distally (often surpassing heads), bases cuneate to attenuate, margins flat, often abundantly long-hispido-strigose along whole, apices acute, sometime mucronulate to white-spinulose, faces sparsely to moderately densely hispido-strigose (2-65 hairs/mm²; hairs often scabrous, ± pustulate), usually eglandular, sometimes sparsely to densely stipitate-glandular. Heads (1-)2-16(-30), in corymbiform arrays, branches ascending. Peduncles 2-16 mm, sparsely to densely hispido-strigose, eglandular or sparsely to densely stipitate-glandular; bracts 1-3, proximal linear-oblanceolate to oblanceolate, sometimes little reduced distally, leaflike. Involucres cylindro-turbinate to narrowly campanulate, (4.5-)5.5-8(-11) mm. Phyllaries in 5-6 series, unequal (outer ¹ / 5 - ¹ / 4 length of inner), narrowly triangular-lanceolate to lanceolate, margins scarious, faces sparsely to moderately strigose, sparsely to densely stipitate-glandular. Ray florets 10-24(-36); laminae (5-)7-11.5(-16.5) × 0.7-1.5(-2.1) mm. Disc florets (12-) 23-55(-70); corollas slightly ampliate, 4.5-7 mm, throats glabrous, lobes 0.4-0.9 mm, lobes sparsely pilose (hairs on lobes 0.1-0.25 mm). Cypselae monomorphic, obconic, compressed, 1.5-2.5(-3) mm, ribs 6-10 (sometimes brownish), faces sparsely to moderately strigose; pappi off-white, outer of linear scales 0.25-0.5 mm, inner of 25-40 br

Heterotheca stenophylla is divided into two varieties that differ in gland and hair density. Their ranges overlap to a great extent, and intermediates occur throughout the range. Both H. stenophylla and H. canescens often have numerous, overlapping leaves and often bear axillary fascicles of leaves.