Flower:

Up to 200 small daisy-like flowers in an open branching cluster at the top of the plant. Flowers are ½ to ¾ inch across with 50 to 100 short, narrow white rays (petals) that may sometimes be pink or bluish tinged, and yellow center disk. Occasionally flowers have very short or nearly no rays. Early heads form at the tip of the branch and nearby lateral buds, later heads emerge from lower leaf axils creating an open array of white blooms.

Behind the flower are 2 to 4 rows of narrow light green bracts that are hairless or sparsely hairy. The flower stalk is ¾ to 1 inch long and also hairless or sparsely hairy.

Leaves and stems:

Leaves are 1 to 6 inches long, ¼ to 1 inch wide, mostly toothless or with a few small teeth, hairless to sparsely hairy, becoming smaller as they ascend the stem.

Leaves near the base are elliptic, spatula-shaped to rounded, tapering to a slender stalk, becoming stalkless and more lance-oblong or linear farther up the stem. Stems are stiff and hairless to sparsely hairy.

Fruit:

Fruit is a small head of nondescript brown seed, each about 1mm long, with a few relatively short light brown hairs attached.

Notes:

The flowers of Prairie Fleabane are very similar to Philadelphia fleabane, (Erigeron philadelphicus), which has toothed clasping leaves, blooms earlier, and is more a woodland species. Also similar is Annual Fleabane (Erigeron annuus), which has broader, more distinctly toothed leaves, is hairier overall, and is generally a taller plant. There are 2 recognized varieties in Minnesota, with a third (var. beyrichii) under review. Var. septentrionalis is uncommon, characterized by flattened (in cross section) appressed to spreading hairs about 1mm long on the stems and flower bracts. Var. strigosus is the more common, with round (in cross section) hairs that are appressed to ascending, up to .5mm long, and more sparse.