Common water-crowfoot

Description

Ranunculus aquatilis, the common water-crowfoot or white water-crowfoot, is a plant species of the genus Ranunculus, native throughout most of Europe and western North America, and also northwest Africa. This is an aquatic plant, growing in mats on the surface of water. It has branching thread-like underwater leaves and toothed floater leaves. In fast flowing water the floaters may not be grown. The flowers are white petaled with yellow centres and are held a centimetre or two above the water. The floater leaves are used as props for the flowers and are grown at the same time. Ranunculus is a large genus of about 600 species of flowering plants in the family Ranunculaceae. Members of the genus are known as buttercups, spearworts and water crowfoots. The familiar and widespread buttercup of gardens throughout Northern Europe (and introduced elsewhere) is the creeping buttercup Ranunculus repens, which has extremely tough and tenacious roots. Two other species are also widespread, the bulbous buttercup Ranunculus bulbosus and the much taller meadow buttercup Ranunculus acris. In ornamental gardens, all three are often regarded as weeds. Buttercups usually flower in the spring, but flowers may be found throughout the summer, especially where the plants are growing as opportunistic colonizers, as in the case of garden weeds. The water crowfoots (Ranunculus subgenus Batrachium), which grow in still or running water, are sometimes treated in a separate genus Batrachium (from Greek βάτραχος bátrakhos, "frog"). They have two different leaf types, thread-like leaves underwater and broader floating leaves. In some species, such as R. aquatilis, a third, intermediate leaf type occurs. Ranunculus species are used as food by the larvae of some Lepidoptera species including the Hebrew character and small angle shades. Some species are popular ornamental flowers in horticulture, with many cultivars selected for large and brightly coloured flowers. Buttercups are mostly perennial, but occasionally annual or biennial, herbaceous, aquatic or terrestrial plants, often with leaves in a rosette at the base of the stem. In many perennial species runners are sent out that will develop new plants with roots and rosettes at the distanced nodes.