Flower:

Clusters of stalked, daisy type flowers 1/3 to ½ inch across with 8 to 20 white petals (ray flowers) and yellow center disk flowers that turn reddish with age. The clusters are variable and may have only a few flowers but are more often tightly packed like a cylindrical spike, sometimes on only 1 side of a branch (secund).

The bracts (phyllaries) surrounding the base of the flower are whitish at the base, narrow with blunt tips and usually peel back away from the base of the flower but may be pressed flat. Flower stalks are hairy with crowded bracts like those at the base of the flowers.

Leaves and stems:

Leaves are mostly linear, up to 2 inches long and less than ¼ inch wide, pointed at the tip, toothless and stalkless, hairless to sparsely hairy on both surfaces and around the edges. There may be smaller leaves clustered in the axils, and the uppermost leaves typically have a tiny, abrupt point or short spine at the tip. Basal leaves are more spatula-shaped but they wither away by flowering time, along with most stem leaves below the branches. Leaves on branching stems are usually much smaller than on the main stem—near the flowers they are very short and more crowded.

Stems are single or multiple from the base, ascending to erect, initially green turning brown and woody, and typically covered in appressed to ascending hairs, especially in the upper plant. Unbranched in the lower plant but often heavily branched above, plants may take on a bushy appearance.

Fruit:

Fruit is a dry seed with a tuft of whitish hairs to carry it off in the wind

Notes:

The leaves of Heath Aster resemble those of 2 other white-flowered asters found in Minnesota. White Prairie Aster (Symphyotrichum falcatum), found primarily in a few western counties but not recorded since 1942, is further distinguished by flowers that are about twice as large and not crowded, and more persistent stem leaves below the flowers. Rayless Aster (S. ciliatum) is an annual preferring moister soils, often found near ponds and other waterways with receding water levels, is mostly hairless, and as the name suggests, flowers that lack rays and appear to be perpetually in bud. There are 2 varieites of S. ericoides, both of which have been recorded in Minnesota: var. pansum, with a single known occurrence at Anna Gronseth Prairie in Wilkin County, is clump forming from a fleshy, bulb-like root (corm), and var. ericoides, widespread in the state and lacks the corm.