tall thimbleweed

Great Plains

Midwest

FACU - Facultative upland

Northcentral & Northeast

FACU - Facultative upland

Native

Common

Moist. Open woods, thickets, river banks. Partial shade.

June to August

White

12″ to 40″

This is an erect, perennial, 12″ to 27″ tall forb rising from a stout, short, ascending to vertical caudex.

A whorl of 1 to 5 basal leaves rises from the ground at the top of the caudex. Basal leaves are on 2″ to 13¾″ long leaf stalks (petioles). The leaf blades are broadly inversely egg-shaped in outline and are divided into three leaflets. The terminal leaflet is unstalked or nearly unstalked, inversely egg-shaped or inversely lance-shaped in outline, ¾″ to 3½″ long, and ¾″ to 4″ wide. It is wedge-shaped to broadly wedge-shaped at the base and is often cut at the tip into 3 lobes. The lobes may be shallow or deep, and often have secondary lobes. The ultimate lobes are sharply pointed. The surfaces are covered with long, soft, straight hairs, more so on the lower surface. The margins are coarsely toothed with sharp, forward pointing teeth. The lateral leaflets are similar but sometimes deeply divided into 2 segments, causing the leaf blade to appear at first inspection to be divided into 4 or 5 segments.

A single flowering stem rises from the caudex at the base of the whorl of leaves. At the top of the stem there is a whorl of 3 leaf-like involucral bracts (sometimes called involucral leaves) and 1 to 9 (usually 3 or fewer) flowering stalks (peduncles). The involucral bracts are conspicuously stalked and similar to the basal leaves.

The inflorescence is a single flower at the end of each peduncle. Each peduncle is 4″ to 12″ long, unbranched, and moderately to densely covered with long, soft, shaggy, unmatted hairs. There are 2 leaf-like secondary involucral bracts usually on all but one of the peduncles that closely resemble the stem leaves. The bracts are usually straight across or almost straight across at the base and straight to concave along the sides. The terminal bractlet is deep green.

The flower is ¾″ to 1″ in diameter. There are no petals, usually 5 petal-like sepals, and 50 to 70 stamens with yellow or light brown anthers. The sepals are oblong to egg-shaped or inversely egg-shaped, greenish-white, ⅜″ to ¾″ long, and ⅛″ to ⅜″ wide.

The infructescence is a dense, cylinder-shaped, thimble-like, ½″ to 1″ long, 5 ⁄16″ to ⅜″ in diameter fruiting head. It appears very prickly.

The fruit is an achene with a tuft of hair attached to the end. In the fall when the achenes mature the fruiting head appears cottony.

Candle anemone (Anemone cylindrica) has a longer, narrower, less prickly fruiting head. It has up to 10 leaves in a whorl at the base of the flowering stalk. There are no leaf-like bracts on any of the flower stalks.

Tall thimbleweed (Anemone virginiana var. virginiana) bracts on the peduncle are heart-shaped or kidney-shaped at the base and straight to convex along the sides. The terminal bractlet is light green. The fruiting head is larger, up to 9 ⁄16″ in diameter.

Tall thimbleweed (Anemone virginiana var. cylindroidea) is found in dry habitats. The petal-like sepals are shorter, usually 3 ⁄16″ to ⅜″ long.

Sources: 4, 24, 28.

Location: Cass County