It is a stout perennial herb growing from a tuberous root and producing an erect stem often exceeding 1 meter (3.3 ft) tall and sometimes approaching 1.2 meters (3.9 ft).
The stem and leaves are usually green but sometimes nearly white in color, smooth below but with rough hairs on the inflorescence.
The leaves are divided into several segments which bear widely spaced leaflets.
The leaflets may also be intricately divided into small segments (see image at left).

The inflorescence is a whitish compound umbel with many branches each up to 10 centimeters long.
The nearly spherical, headlike terminal umbellets contain many tiny white or purple-tinged flowers, whose protruding stamens make them appear very fuzzy in full bloom, as for the central umbels in the top right image.
It is a stout perennial herb growing from a tuberous root and producing an erect stem often exceeding 1 meter (3.3 ft) tall and sometimes approaching 1.2 meters (3.9 ft). The stem and leaves are usually green but sometimes nearly white in color, smooth below but with rough hairs on the inflorescence. The leaves are divided into several segments which bear widely spaced leaflets. The leaflets may also be intricately divided into small segments (see image at left).
The inflorescence is a whitish compound umbel with many branches each up to 10 centimeters long. The nearly spherical, headlike terminal umbellets contain many tiny white or purple-tinged flowers, whose protruding stamens make them appear very fuzzy in full bloom, as for the central umbels in the top right image.
Sphenosciadium