An annual found in a highly specialised marshy habitat. It requires winter inundation, bare, wet mud for seedling establishment, reduced summer water levels and low competition. The substrate at the two extant sites is base-rich Lias clay, with most water input from rain. Lowland.
Sites in S. Hampshire, Dorset and Jersey were lost by the early twenteenth century. The largest surviving population, at Badgeworth (E. Gloucs.), has been dependent on management since 1962, and with appropriate human disturbance a sizeable population of plants flower and fruit every year. A smaller site nearby is still managed by grazing, and that population is more erratic.
European Southern-temperate element.
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Light (Ellenberg): 7
Moisture (Ellenberg): 8
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 5
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4.9
July Mean Temperature (Celsius): 16.5
Annual Precipitation (mm): 824
Height (cm): 40
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 4
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 2
Plantatt Conservation Status
RDB Species Accounts
Ranunculus ophioglossifolius Villars (Ranunculaceae)
Adder's-tongue spearwort, Llafnlys Tafod y Neidr
Status in Britain: ENDANGERED. WCA Schedule 8.
Status in Europe: Not threatened.
In recent years, R. ophioglossifolius occurs in only two sites in Britain, at Badgeworth, and at Inglestone Common, both in Gloucestershire. It is a plant of semi-permanent ponds and marsh. At its main site, Badgeworth, the plants grow in a depression in surrounding flat meadowland, on impervious Lias clay, which fills up seasonally with rain water. Periods of heavy rain can lead to dramatic rises in water level. Associated species include Alopecurus geniculatus, Eleocharis palustris, Glyceria fluitans and Myosotis scorpioides. The site at Inglestone is also a pond on Lias clay, though there is at present almost no open water. Species occurring in the swampy grassland include Carex disticha, Glyceria fluitans, Juncus effusus, J. inflexus, Ranunculus flammula, R. repens, R. trichophyllus and Senecio aquatilis.
It is an overwintering annual. For optimal growth it requires bare, moist soil from August to October with an absence of frost for germination and seedling growth, sufficient winter rain to submerge the plants, and a reduction of water level in spring (Dring & Frost 1971; Holland 1977). The germination stage is particularly sensitive, and autumn frosts may destroy every seedling. Seeds can also germinate the following spring, though the resultant plants are stunted and may not exceed 3 cm in height, whereas autumn-germinated plants generally grow to 40-50 cm (Dring & Frost 1971; Holland 1977; Jones 1978). Seeds can remain viable for at least 30 years, but are killed by prolonged desiccation (Jones 1978; Toase 1992). Populations vary greatly in response to climatic conditions, and during peak years at Badgeworth, more than a thousand plants may flower, though in poor years there may be none (Holland, et al. 1986; Doe 1993). At Inglestone Common, about 100 plants flowered in 1966 following vegetation clearance, but in recent years there have been few plants, and often none at all (Rich 1993b; Kitchen, et al. 1995). In 1993-5, only 1, 5, and 2 plants were recorded, but in 1996 cattle were excluded during the flowering and fruiting season, and 36 plants were seen inside the fence, and nine outside it (Rich & Davis 1996).
It was formerly known from two other sites in Britain, in Hampshire (one record, 1878) and Dorset, but both were lost to drainage and development by the early part of this century. It has been protected at Badgeworth since the establishment of the reserve (now an NNR) in 1933, and the reserve is further protected within a larger SSSI. Since 1962, the area has been actively managed for R. ophioglossifolius, which crucially includes each year the creation of patches of bare ground for germination (Holland 1977; Frost 1981). Within a small area of the reserve, grazing by cattle and horses between mid-July and late September has also been beneficial, since this also provides the necessary disturbance and control of competing species, particularly Glyceria fluitans. The site at Inglestone Common is within the Lower Woods SSSI. Some beneficial management was carried out in past years, and following a period of neglect, habitat management has resumed (Rich 1993b).
R. ophioglossifolius is widespread in southern Europe, from Spain to Greece and the Crimea, with disjunct populations in England and Gotland (Holland 1977). It also occurs in North Africa and West Asia. It is extinct in Jersey. The Badgeworth and Inglestone plants are morphologically similar to the large-flowered var. genuinus, but a taxonomic review of the species is required before any firm conclusions can be drawn (Dring & Frost 1971; Frost 1981). Nonetheless, plants from Badgeworth have been shown to be genetically distinct from Portuguese material (Frost 1981).
D. A. Callaghan
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1989)
1999. Britain's rare flowers.
1999. British Red Data Books. 1. Vascular plants, edn 3.