Flower:

Between 1 and 15, long-stalked, daisy-like flowers in an open branching cluster at the top of the stem and arising from upper leaf axils. Flowers are 1 to 2 inches across with 125 to 175 narrow rays (petals) around a yellow center disk 1/3 to ¾ inch across. Ray color is violet to purple to pinkish, sometimes white.

Behind the flower are 2 to 4 layers of narrow bracts, light green and often purple tipped, sparsely to moderately covered in short, appressed to spreading hairs. Flower stalks are stiff, to 3+ inches long and also sparsely to moderately hairy.

Leaves and stems:

Leaves are both basal and alternate on the stem, lowest leaves oblong to narrowly spatulate, usually widest above the middle (oblanceolate), 2 to 6 inches long, 1/3 to 2/3 inch wide, rounded to bluntly pointed at tip with a long taper to a short stalk. Edges are toothless or obscurely toothed or shallow lobed, surfaces smooth to sparsely covered in short, stiff hairs.

Leaves become smaller as they ascend the stem, becoming more lance-elliptic and stalkless, the uppermost leaves somewhat clasping the stem. Stems are single from each basal leaf cluster, erect to ascending, unbranched except in the flower clusters, and variously short hairy with appressed or spreading hairs. Small colonies may be formed from short rhizomes.

Fruit:

Fruit is a small light brown seed, the surface stiff-hairy, each about 1.2 to 1.5 mm long, with 2 rows of short bristles on top.

Notes:

Smooth Fleabane is fairly well separated into two distinct ranges in Minnesota, where highest concentrations are throughout our northwestern counties and then a smaller range limited to Carlton and Pine counties that are continuous with several adjacent counties in northwest Wisconsin. There are two recognized varieties: var. glabellus is found throughout much of the western Great Plains, extending to northeast North Dakota along our western border, and is distinguished by its sparsely to nearly hairless stems, the hairs short, stiff and appressed or ascending; var. pubescens is the one found in Minnesota and WI, with more consistently hairy stems, the hairs soft and spreading. While var. glabellus has not been recorded in MN, it is quite possibly here nonetheless.

White-flowered Smooth Fleabane might be confused with either Philadelphia Fleabane (Erigeron philadelphicus) or Prairie Fleabane (E. strigosus), but both are annual or biennial with typically several stems from basal clumps, are much taller, have smaller flowers, and are more heavily branched with more flowers per cluster. It is more likely to be confused with Robin's Plantain (E. pulchellus), though there is little overlap with their ranges. Both are perennial, rhizomatous, have single stems from each basal leaf cluster with larger and fewer flowers per cluster than other Fleabanes. But E. pulchellus rarely has more than 4 flowers per cluster, is more densely hairy throughout with soft, spreading hairs, has shorter basal and stem leaves (3 inches or shorter) that are more broadly oblong, basal leaves are more egg-shaped with short tapered bases, the flower stalk is more or less inflated just below the involucre (set of bracts), and blooms earlier, starting in mid-spring.

Key characteristics to look for in E. glabellus are its large flowers (1 inch or larger), few flowers per cluster (15 or fewer), generally sparsely hairy leaves and stems especially upper stem and leaf surfaces, long narrow oblong-elliptic or oblanceolate leaves up to 6 inches long. It is somewhat rhizomatous, with only one stem per basal leaf clump, colonies often sparsely spreading with both flowering and non-flowering leaf clumps. The deeper violet-flowered form is highly diagnostic in Minnesota populations, not likely confused with other Fleabanes but may be mistaken for a purple-flowered Symphyotrichum (Aster) species, though Fleabane flowers have many more rays than any of the Asters.