Flower:

Flowers are in an open branching cluster (panicle) at the top of the plant. Individual flowers are about 1 to 1½ inches across with 12 to 25 pale blue ray flowers (petals) and yellow center disc flowers that turn red with age.

The bracts are narrow, flattened, and a bit irregular, sometimes tinged purple at the tips. The flower stalks are of varying lengths, with a few narrow leaf-like bracts along a stalk. A plant typically has fewer than 50 flowers.

Leaves and stem:

Leaves are generally heart-shaped, to 5 inches long and 2 inches wide with a sharply pointed tip and “winged” leaf stalk. Edges are toothed with fine hairs all around the edge and hairy on the underside to varying degrees. Leaves near the base of the plant have long stalks with narrower wings, becoming shorter stalked with wider wings as they ascend the stem. Leaves nearest the flowers may have no stalk. The lower leaves may wither away and drop off by flowering time. The main stem may be green or reddish and hairy to varying degrees, especially near the flowers.

Notes:

Lindley's Aster is one of the more common blue asters in Minnesota, found in most counties from the Metro north, and seen along roadsides on the North Shore in late summer. Asters can be difficult to ID. Lindley's Aster is distinguished mostly by its leaves, which have broadly winged stalks and toothed edges. Most closely resembling it is Blue Wood Aster (Symphyotrichum cordifolium) but that species has only slightly winged leaf stalks, if any, and its flowers may have as few as 8 rays. White Arrow-leaved Aster also has winged stalks, but smaller white flowers in more densely packed clusters.