Threadleaf crowfoot

Description

Ranunculus trichophyllus, the threadleaf crowfoot, or thread-leaved water-crowfoot, is a plant species in the genus Ranunculus, native to Europe, Asia and North America. It is a herbaceous annual or perennial plant generally found in slow flowing streams, ponds, or lakes. The daisy-like flowers are white with a yellow centre, with five petals. It is similar in form to Ranunculus fluitans (river water-crowfoot), apart from flower petal number, thread-leaved has on 5 petals and shorter leaves, as thread-leaved prefers slower flowing waters. It also has rounded seed heads which become fruits covered with bristles. The segmented leaves and the plants ability to photosynthesis underwater have been studied. The plant is found in most of the Northern Hemisphere, from the United States, Europe and the Mediterranean, east through Siberia, the Caucasus, the Middle East, the Himalayas, Kazakhstan and Mongolia to Kamchatka in Russia, also in Japan, China and Korea. It is even found in the lakes and ponds of Mount Everest. It was first described and published by the French naturalist and botanist Dominique Villars in his book 'Histoire des plantes du Dauphiné' Vol.3 on page 335 in 1786. The species epithet trichophyllus is Latin for 'hairy leaves'. In American it is also commonly known as the 'white water crow foot'. The Icelandic name of this species is Lónasóley. Subspecies: Ranunculus trichophyllus subsp. eradicatus (Laest.) C.D.K.Cook (synonym: Batrachium eradicatum (Laest.) Fr.) 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").