Range & Status
Widespread around the Mediterranean, extending up the Atlantic coast of Europe to the Channel Isles and SW. England; also W. and S. Africa and Macaronesia. In the British Isles, known only in W. Cornwall and Isles of Scilly.
Known only in Scilly and on the Lizard Peninsula.
Habitat & Ecology
Grows in short grassland and on bare patches of acidic soil, usually where the soil is thin overlying rocks (serpentine on the Lizard; often over granite in Scilly). It occurs on rocky slopes, in damp hollows on coastal heaths and on roadside banks near the sea, in sites that are damp or wet in winter but subject to summer drought. It often ' disappears' in summer, presumably surviving as tuberous underground stems. Apparently varies in frequency from year to year, being commonest after dry summers which reduce competition from vascular plants followed by wet winters. Malloch (1972) gives a detailed description of its habitat
on the Lizard. It is a dioicous species for which neither male plants nor sporophytes have been recorded in Britain. Jones (1964) describes sporophytes from W. African plants.
Plenty of suitable habitat remains at its sites on the Lizard. It is associated there with nationally rare Riccia species and vascular plants (including Land Quillwort Isoetes histrix ) at some of the sites. Apparently lost from the Garrison (St Mary' s, Isles of Scilly) due to heathland vegetation becoming taller and denser.
Its sites on the Lizard and several of those in Scilly are within SSSI.