Rudbeckia triloba var. triloba

Native

Minnesota special concern species

Wet to moderate moisture. Openings or lightly shaded areas in moist hardwood forests and floodplain forests, thickets, roadsides, and disturbed areas. Full or partial sun.

Early August to mid-September

Yellow ray florets, brownish-purple disk florets

12″ to 60″

This is an erect, biennial or short-lived perennial forb that rises on one to several stems from rhizomes and shallow, fibrous roots. It can be 12″ to 60″ tall, though in Minnesota it is usually no more that 40″ in height at maturity.

The stems are erect, green, and ridged. They are frequently branched above the middle, giving the plant a bushy appearance. They are sparsely to moderately covered with conspicuous, white hairs, especially toward the top. The hairs near the top of the stem are mostly spreading, those near the base mostly pointed downwards. The stems are sometimes hairless near the base. They are not covered with a whitish, waxy coating (glaucous).

Basal leaves are on long, mostly winged leaf stalks. The blades are 4″ to 11¾″ long, ¾″ to 3″ wide. They are egg-shaped to broadly egg-shaped in outline. They are tapered to slightly heart-shaped at the base. At least some of the larger leaves are usually deeply divided into 3 lobes. The lobes are egg-shaped or lance-shaped and are tapered to a sharply-pointed tip. The upper and lower surfaces are moderately covered with conspicuous, white, spreading hairs and with minute, yellow glands. They are slightly rough to the touch and are not glaucous. The margins are usually toothed with sharp, forward-pointing teeth.

Lower stem leaves are alternate, up to 8″ long and 3″ wide, and otherwise similar to basal leaves. Basal and lower stem leaves are often absent at flowering time. Stem leaves become smaller, less divided, and shorter-stalked as they ascend the stem. Middle and upper stem leaves are stalkless or on short, winged leaf stalks. Upper leaves sometimes clasp the stem. Middle and upper leaf blades are up to 4¾″ long, up to 1¼″ wide, narrowly lance-shaped, egg-shaped, or elliptic, rounded at the base, and tapered to a sharp point at the tip.

The inflorescence is a loose, open, branched cluster (panicle) of 10 to 30 flower at the end of the stem and branches. The bracts at the base of the flower head are ¼″ to ½″ long, lance-shaped to linear, bent backward, and moderately hairy.

The flower heads are 1″ to 1¾″ in diameter. There are 8 to 15 yellow ray florets and 100 to 300 or more dark brownish-purple disk florets. The disk is 3 ⁄16″ to ⅜″ in diameter and is in the shape of a flattened cone. The flowers are not fragrant.

The fruit is a dry, black, oblong, 4-angled, 1 ⁄16″ to ⅛″ long cypsela with no fluffy tuft of hairs attached.