Apium (Celery and Marshwort) is a genus of about 20 species of flowering plants in the family Apiaceae, with a subcosmopolitan distribution in Europe, Asia, Africa and South America. They are medium to tall biennial or perennial plants growing wet ground (marshes and saltmarshes). They grow up to 1 m high and have pinnate to bipinnate leaves and small white flowers in compound umbels.