The narrow, cylindrical, rayless flowerheads of
eucephalus breweri are formed of around ten to 20 yellow disc florets, which produce protruding yellow stamens and divided, yellow-brown styles when mature. Florets around the edge mature first. The green phyllaries are approximately equal in length, have pointed tips and a light tomentose hair covering, and tend to curve outwards, away from the involucre. Stems and leaves have a similar covering of hairs. Long white bristles protrude above the upper row of phyllaries. Flowerheads form small, open clusters. Stem and leaves are usually glandular. This species is found mostly in the Sierra Nevada, extending to the southern Cascade Range.