Slender, erect stem. Leaves near the base of the plant have blades up to 35 cm long, divided into many narrow, subdivided lobes. Upper leaves are smaller and less divided. Leaves are usually withered by flowering time. Late-flowering plants have been seen into October. The inflorescence is a compound umbel with 7–14 unequal rays with 0–2 bracts at its base. Each of the secondary umbels has 15–40 flowers and 8–13 bractlets. The ovary is inferior ovary with a +/- persistent conical projection subtending two 1–2 mm, slender styles. The fruit is roundish, as broad as long.