tall thimbleweed

not listed

N5 - Secure

SNR - Unranked

not listed

FACU - Facultative upland

FACU - Facultative upland

FACU - Facultative upland

Tall thimbleweed (var. alba) is an early summer wildflower. It occurs in the United States from Maine to New Jersey, west to Minnesota and northern Iowa, and in adjacent Canadian provinces. It is found on moist cliffs and ledges and in areas bordering rivers (riparian areas). This is the feature that gives the subspecies its common name.

Tall thimbleweed (var. alba) is an erect, perennial, 12″ to 27″ (30 to 100 cm) tall forb rising on basal leaves and a single stem 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. Each basal leaf is on a 2″ to 13¾″ (5 to 35 cm) long leaf stalk (petiole). The petiole is often purplish and is shallowly grooved above. The leaf blade is broadly inversely egg-shaped in outline and is divided into three leaflets. The terminal leaflet is unstalked or nearly unstalked, inversely egg-shaped or inversely lance-shaped in outline, ¾″ to 3½″ (3 to 9 cm) long, and ¾″ to 2″ (2 to 5 cm) wide, sometimes larger. 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 upper and lower 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. The stem is covered with scattered white hairs and is usually unbranched below the inflorescence. At the top of the stem there are two or three pairs of opposite whorls of inflorescence leaves (bracts). Each whorl has 3 or 4 bracts (together called an involucre). The bracts are conspicuously stalked and are similar to the basal leaves but are smaller. The base of each bract is usually straight across (truncate) ot almost truncate, but is sometimes kidney-shaped or heart-shaped. The margins are coarsely toothed on the upper half and sometimes also lobed. The terminal leaflet is dark green, elliptic to inversely lance-shaped, ¾″ to 4″ (2 to 10 cm) long, and ¾″ to 2″ (2 to 5 cm) wide. It is wedge-shaped at the base and sharply pointed at the tip. The margins of the terminal leaflet are concave to straight and untoothed on the lower half. The upper surface is thinly hairy.

A long stalk (peduncle) with a single flower rises from the upper axil of some of the bracts. Each peduncle is 4″ to 12″ long, unbranched, and moderately to densely covered with long, soft, shaggy, unmatted hairs. A secondary involucre on each peduncle appears at least 4¼″ (11 cm) below the flower. The bracts of the secondary involucre are much smaller. The terminal leaflet is no more than ¾″ (2 cm) in length.

The inflorescence is a single flower at the end of each peduncle. Each flower is ¾″ to 1″ (20 to 25 mm) in diameter. There are no petals, usually 5 sepals, and 50 to 70 stamens. At the center of the flower there is a dense cluster of green pistils. The sepals are petal-like, oblong to egg-shaped or inversely egg-shaped, white or greenish-white, ¼″ to ¾″ (6.5 to 20 mm) long, and ⅛″ to ⅜″ (2.5 to 10 mm) wide. They are thinly hairy on the outside, hairless or nearly hairless inside. The stamens form a ring around the base of the cluster of pistils. The anthers are yellow and 1⁄32″ to 1⁄16″ (1.0 to 1.7 mm) long. They turn light brown after shedding pollen.

The infructescence is a dense, cylinder-shaped fruiting head. The cluster of pistils elongates, becoming ½″ to 1⅛″ (12 to 28 mm) long and 5⁄16″ to ⅜″ (8 to 10 mm) in diameter. Its shape resembles a thimble. This is the feature that gives the species its common name. The “thimble” is less than twice as long as wide. It appears very prickly.

The fruit is an egg-shaped to egg cylinder-shaped, 1⁄16″ to ⅛″ (2.0 to 3.7 mm) long seed capsule (achene). Dense woolly hairs conceal only the lower half of the achene. When the achenes mature in the fall the fruiting head appears cottony and remains so all winter.

12″ to 40″

White

Tall thimbleweed (Anemone virginiana var. cylindroidea) involucral bracts are more or less light green. The flowers are much smaller. The sepals are (5 to 10 mm) long and are densely tomentose. The anthers are shorter, no more than 1⁄32″ (1.2 mm) long. The fruiting head is smaller, ¼″ to 7⁄16″ (7 to 11 mm) in diameter.

Tall thimbleweed (Anemone virginiana var. virginiana) involucral bracts are heart-shaped or kidney-shaped at the base, rarely truncate. The terminal leaflet is light green. The margins of the terminal leaflet are straight or convex on the lower half.

Riparian areas and moist cliffs and ledges

May to July

Sources

4, 28.

According to the Minnesota Department of Natural Resources (DNR) and Minnesota Biodiversity Atlas: Bell Museum plants, Anemone virginiana var. alba is the most common variety, and it occurs throughout Minnesota except in the southwest corner. According to Flora of North America (FNA), A. v. var alba is restricted to the eastern border counties from Carlton County to Houston County. It is found in areas bordering rivers (riparian areas) and on moist cliffs and ledges.

The dark green on the map includes only counties with records within the range circumscribed by FNA. The light green includes other counties with records reported by the Minnesota DNR, Bell Museum, and by Global Biodiversity Information Facility (GBIF), which includes the Bell Museum plants dataset.

Native

Common