Flower:

Small clusters (umbels) at the ends of branching stems, made up of 1 to several small round clusters (umbellets) about ½ inch across and consisting of 20 to 60 flowers each. Flowers are either male or perfect (both male and female parts), with both present in an umbellet. Flowers are dull yellow to greenish yellow with 5 petals much longer than the sepals, and protruding stamens with yellow tips that turn brown with age.

Perfect flowers are nearly stalkless, have a small ovary covered in short bristles, and 2 long spreading styles that are much longer than the bristles. The styles persist and become arching in fruit.

Leaves and stems:

Leaves are palmately compound, mostly with 5 leaflets or 3 in the upper plant, generally alternately attached, but can be opposite or basal. Leaflets are up to 2 inches long and to 1 inch wide, coarsely toothed, hairless, elliptical to triangular shape and usually widest above the middle, often with notches or shallow lobes on the tip half. Lower and basal leaves are long stalked, becoming stalkless or nearly so in the upper plant. Stems are single or multiple from the base, erect, hairless, and branched in the upper plant.

Fruit:

Fruit is round, dry, less than ¼ inch long and covered in short, hooked bristles, the remains of the style usually persisting and arched. The fruit splits into 2 seeds.

Notes:

This species often goes by Sanicula gregaria. There are 4 Sanicula species in Minnesota, all with similar "pom-pom" like flower heads and palmately compound leaves. The flowers of Clustered Black Snakeroot are distinctly yellowish compared to the others, which are all greenish or creamy white. When fruiting, the shorter bristles and long curved style distinguish it from Canadian Black Snakeroot (Sanicula canadensis), which also has its lower leaves compound in 3s, though deeply cleft to look like 5. Maryland Black Snakeroot (Sanicula marilandica) has leaves with 5 to 7 leaflets. The fourth species, Beaked Snakeroot (Sanicula trifoliata), is rare in Minnesota, has male flowers on relatively long stalks, and fruits about 1/3 inch long.