Plant: Plant 10-15 dm, Perennial, glabrous; rhizome divided internally into chambers, with sap that oxidizes to reddish brown; stem erect, hollow Leaves: 1-4 dm, ovate to triangular-ovate, 1-2-pinnate; leaflets 2-10 cm, lanceolate, acute or acuminate, coarsely to sparsely serrate, areas surrounded by veins on lower surface fine, generally rounded or square INFLORESCENCE: umbels compound, terminal and lateral; peduncles 2.5-12 cm; rays 15-30, 2-4.5 cm; pedicels 15-30, 2-10 mm Flowers: many, small; calyx lobes minute; petals 5, wide, free, white, tips narrowed; stamens 5; pistil 1, ovary inferior, 2-chambered, generally with a ± conic, persistent projection or platform on top subtending 2 free styles Fruit: 3-4 mm, generally ovate, slightly compressed side-to-side; ribs ribs low, corky, sometimes unequally spaced, generally as wide as to much narrower than intervals between; oil tubes per rib-interval 1; fruit axis divided to base; Seed: face flat or concave Misc: Wet places; < 2000 m.