Hypericum undulatum Wavy St. John's-wort R DD N
This is a square-stalked St John's-wort found in damp places so at first you might think it was H. tetrapterum (Square-stalked St John's-wort) which is much commoner. The next observation is that the flowers with red tinged petals underneath look more like H. pulchrum (Slender St. John's-wort). Finally the characteristic which gives the plant its name and is less obvious is the leaves: they are sessile (without stalks) and have distinct wavy edges with many translucent dots - more even than H. perforatum (Perforate St John's-wort). There were black glands on some of the flowers on this specimen and even on the anthers!
This plant has a very localised southwestern distribution. It is found in south west Wales but most is to be found in Cornwall and a little in Devon. There is none to be found in Scotland, Ireland or elsewhere in England.
Edge of path round upper Tamar Lake, Cornwall 19th July 2008
Added on 24th July 2008, updated 17th December 2009, updated 7th April 2010, updated 28th July 2013