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.
This ascomycete fungus was added to the British List in 1973 and was subsequently recorded from three sites on the extreme north-east Cornwall border with Devon in 1988. It has since been recorded from Lower Lewdon nature reserve (Cornwall Wildlife Trust), Valency Valley (Boscastle) and very recently, 2007, on Hazel Corylus avellana at an inland site at Wringworthy south of Liskeard. H. rhododendri has a western (Atlantic) or oceanic European distribution which is most often encountered on living, senescing or dead stems of Hazel, especially in undisturbed areas which are not subject to intense woodland shade. It is also occasionally found on Blackthorn Prunus spinosa , and Willow Salix spp. Western Scotland, Eire, Devon and Cornwall are the strongholds for this hyperoceanic species in Britain. Other sites with stands of Atlantic Hazel/Blackthorn woodland, of which there are many, should be surveyed. In existing sites some of the Hazel stands need to be very slightly cut to provide a ' reservoir' of dead and senescing wood that this species seems to like. H. rhododendri is a Biodiversity Action Plan (BAP) species with a Species Action Plan (SAP). Ainsworth (2003) has reviewed the current status and conservation concern
00 of this species.
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.