Perennial herb, 60-150 cm tall, the entire plant covered with a powdery frost-like surface, hairless, with fennel emitting a strong aroma. The stem is erect and branched. Leaves are tripinnate to quadripinnate compound, with ultimate leaflets linear, 4-40 mm long, about 0.5 mm wide; petiole about 14 cm long, base sheathing and clasping the stem. Compound umbels terminal; peduncle 4-25 cm long, both involucre and bracteoles absent; rays 8-20, unequal in length; flowers small, yellow; calyx teeth absent; petals 5, broadly ovate, upper part involute and slightly concave; stamens 5, longer than the petals; ovary inferior, 2-celled, styles 2. Fruit is a schizocarp, oblong, with 5 prominent ridges, flowering period June to July, fruiting period September to October.