Flowers, bracts and leaves of symphyotrichum laeve
are usually hairless, hence the common name of smooth aster, but may be covered by a whitish bloom. Flowers are slightly less than an inch across, and form broad, open clusters typically containing 10 to 20 heads. The involucres are cylindrical or bell-shaped, lined by several series of small, non-overlapping phyllaries, often with a dark tip, and not glandular (nor sticky). The purple-lavender ray florets usually number from 13 to 23, the yellow-purple disc florets 19 to 33. Leaves are thick and fleshy, and their edges are usually lined by very fine teeth. This is a late-blooming species, adding color to the lower mountain slopes into early fall.