Dicot.  Very small flowers arranged in umbels.  Sepals tiny or lacking.  Petals 5 with incurved tips.  Stamens 5, alternating with the petals and inserted on a disk.  Aromatic herbaceous plants, the leaves alternate or basal, compound, with petioles anlarged and sheathing the hollow stem at the nodes.  Seeds two-parted, separating at maturity and containing aromatic oils.