Orobanche picridis Oxtongue Broomrape

Oxtongue Broomrape is a very rare, red-listed parasitic flowering plant in the British Flora which, until recently, was only known (post 1950) from a few sites in the south of England. Remarkably, it was discovered by Darryl Spittle in an open mosaic industrial site in Margam in 2021 and subsequent surveys have revealed that it is present in significant numbers in the vicinity of Port Talbot. More recently, it has been discovered on a brownfield site in Swansea and appears to be undergoing a local range expansion. Oxtongue Broomrape is easily confused with pale coloured morphs of Common Broorape (Orobanche minor) which is a common and variable species in West Glamorgan. In fact BS and CH have photographic evidence that the species has been present in the Margam area for at least 13 years prior to its recent discovery, but both had misidentified it as a pale morph of Common Broomrape. More significantly, a specimen collected in 1910 by Riddlesdell from Port Talbot Docks (where it still occurs) and deposited in the British Museum appears to be Oxtongue Broorape, although this is not mentioned in his flora. Important features that distinguish it from Common Broomrape include the dark purple (almost black) stigma that contrasts with the whitish to pale yellow corolla and the dark and strikingly long, recuved bracts which subtend the flowers. The straight back to the corolla is also quite distinctive compared to the more curved profile of Common Broomrape's corolla. Oxtongue Broomrape parasitises Hawkweed Oxtongue (Picris hiercioides) almost exclusively in Britain and its recent range expansion in West Glamorgan follows the large population expansion of its host in coastal parts of the county, which has occured in the last few decades. Hybrids between Oxtongue Broorape and Common Broomrape have also been identified in Port Talbot. Whether the recently discovered population is linked with populations that may have been present in the county over 100 years ago, or whether they have a different origin, is not clear. However, evidence that it may have been more widespread in south Wales in the past is suggested from the discovery by Tim Rich that a specimen in NMW collected in 1926 from Swanbridge (Vale of Glamorgan) that had been identified originally as Orobanche minor was redetermined as Orobanche picridis (BSBI Welsh Bulletin, May 2024, p 52). 

Possibly native but the current population may be neophyte and derived from introduced seed.