Apium L. >
Stems prostrate or ascending or rarely erect. Leaves once or twice pinnatisect, often rather thick; the segments tripartite. Compound rays 3–6, each with an umbel of rather numerous small white flowers. Fruit c. 3 mm long; mericarps with 5 thick ribs. Small perennial with a thick rootstock. Sea Celery
Leaflets divided or entire, primary segments 6–15 times as long as broad. Near inland creeks and brackish water. Fl. spring–summer Apium prostratumprostratum