Celery (Apium graveolens) is a marshland plant in the family Apiaceae that has been cultivated as a vegetable since antiquity. Celery has a long fibrous stalk tapering into leaves. Depending on location and cultivar, either its stalks, leaves or hypocotyl are eaten and used in cooking. Celery seed powder is used as a spice. Celery leaves are pinnate to bipinnate with rhombic leaflets 3–6 centimetres (1–2+1⁄2 inches) long and 2–4 cm (1–1+1⁄2 in) broad. The flowers are creamy-white, 2–3 mm (3⁄32–1⁄8 in) in diameter, and are produced in dense compound umbels. The seeds are broad ovoid to globose, 1.5–2 mm (1⁄16–5⁄64 in) long and wide. Modern cultivars have been selected for either solid petioles, leaf stalks, or a large hypocotyl. A celery stalk readily separates into 'strings' which are bundles of angular collenchyma cells exterior to the vascular bundles. (Source: Wikipedia.org, CC BY-SA)