The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
An uncommon variety of a relatively common species, recorded from Britain, Ireland,
Germany, Hungary, Italy and Dalmatia. In the British Isles it is known mainly from chalkland regions of S. England, with other records from Yorkshire and W. and N. Ireland. It is a poorly known and little understood form (cf. Paton, 1969; Smith, 2004) that was apparently omitted in error from the national Atlas (Hill et al ., 1994).
The only recent record was from Roseland (SX26R) in 2006. There are several older
records, from Hayle, south of Coverack in 1927, Kennack Sands in 1933 and Portnadler near Looe in 1917 (cf. Paton, 1969).
Habitat & Ecology
At Roseland found on damp soil among slaty rocks on a bank near a disused quarry.
Older Cornish records were from moist banks on the coast. Elsewhere, this variety occurs in grassland on chalky and calcareous soil. The species is dioicous and capsules are rare (perhaps unrecorded in var. calcarea ).
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.