Celery leaves are pinnate to bipinnate with rhombic leaflets 3–6 cm (1.2–2.4 in) long and 2–4 cm (0.79–1.57 in) broad. The flowers are creamy-white, 2–3 mm (0.079–0.118 in) in diameter, and are produced in dense compound umbels. The seeds are broad ovoid to globose, 1.5–2 mm (0.059–0.079 in) long and wide. Modern cultivars have been selected for solid petioles, leaf stalks. A celery stalk readily separates into “strings” which are bundles of angular collenchyma cells exterior to the vascular bundles. Head of celery, sold as a vegetable. Usually only the leaf stalks are eaten Wild celery, Apium graveolens var. graveolens, grows to 1 m (3.3 ft) tall. It occurs around the globe. The first cultivation is thought to have happened in the Mediterranean region, where the natural habitats were salty and wet, or marshy soils near the coast where celery grew in agropyro-rumicion-plant communities.^. North of the alps wild celery is found only in the foothill zone on soils with some salt content. It prefers moist or wet, nutrient rich, muddy soils. It cannot be found in Austria and is increasingly rare in Germany