Adder's-tongue spearwort is related to the buttercup, and an alternative name for it is the 'Badgeworth buttercup' (3). The Latin name Ranunculus means 'froglike' and refers to the plant's preference for aquatic habitats. When submerged, the pale greenish-yellow leaves float to the surface like small water-lily leaves (3). The flowers are small and yellow (3). The specific part of the scientific name, ophioglossifolius refers to the fact that the leaves are shaped like the small fern Ophioglossum(4).
This annual plant has very precise needs. From August to October bare, damp soil is essential to allow germination to occur. During winter the plants need to be submerged so that they can survive, and the water level must fall in spring. The number of plants present at a site each year can vary enormously, and depends on climatic and management factors (3).
At present, this species is known from just two sites in the UK, Badgeworth and Inglestone Common, both in Gloucestershire (2). It has previously been recorded in another 2 sites in southern England (4). Elsewhere the species occurs widely throughout southern Europe, as well as in North Africa and western Asia (2).
Known threats are drainage and development of suitable habitats (2). The Badgeworth site was threatened by the proposed development of a plant-hire vehicle wash-down area nearby, but fierce opposition from local people saved the site from the inevitable pollution that would have occurred (3). Lack of management of the pond at Inglestone is also a threat (4).
The Badgeworth site is the smallest nature reserve in Britain (3), and is located in a Site of Special Scientific Interest (SSSI) (2). The site is managed in ways that benefit adder's-tongue spearwort; bare patches are made each year to allow the species to germinate, and livestock have been allowed to graze in certain areas to keep competing species at bay. The Inglestone site is an SSSI, and although the site was neglected in the past, suitable management is now underway (2). Adder's-tongue spearwort is one of Plantlife's 'Back from the Brink' species (5).
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