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Cornish Red Data (2009)

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.

Hypericum undulatum - Wavy St John's-wort

Range & Status

Native. Oceanic Southern-temperate. In Britain it is confined to Cornwall, Devon and west Wales, and most common in Cornwall.

Regional Distribution

It is classically associated with Culm Measures grassland in north-east Cornwall, but is also found in West Penwith and The Lizard and in an areas between Wadebridge (SW97) and Truro (SW84). Scattered in south-east Cornwall and possibly under-recorded.

Habitat & Ecology

Mostly in marshes and damp heaths. Small rush-pasture vegetation in the bottom of the numerous small valleys common in Cornwall seem to be a typical habitat where it may grow with Square-stalked St. John' s-wort Hypericum tetrapterum : the hybrid between the two (new to science) has been confirmed recently in two such sites in east Cornwall and is worth looking for elsewhere.


The scrubbing over of marshes and wet rushy meadows by Grey Willow Salix cinerea subsp. oleifolia threatens a lot of sites, and small areas of such habitat remain susceptible to drainage, infill or inappropriate management. However disturbance, especially by grazing cattle, appears to increase habitat for colonisation as it has a large seed-bank.


Very few sites are protected.

Click here to see Aphotoflora images by David Fenwick


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.