Draba aizoides Yellow Whitlowgrass

A  perennial crucifer that grows in cushions with clusters of yellow flowers that appear in early spring. It is widely distributed in calcareous habitats in mainland Europe, almost entirely as a mountain or alpine species, from the Pyrenees, through the central Alps and eastwards to the Carpathian Mountains and with a somewhat isolated occurrence in Belgium. Its disjunct occurrence in Gower, its only location in Britain, where it grows on the south-facing limestone cliffs of south Gower and on the walls of Pennard Castle, is remarkable. In the past there has been some debate as to whether it originated as an introduction in Gower, which subsequently spread on to the cliffs or whether these populations are truly native. However careful analysis of the allele frequencies of the Gower populations and various, different European populations by Rosemary John in the 1980s, in Swansea Univerity, showed that there is a marked genetic separation between plants fom Gower populations and plants from the European mainland, which suggests that they have been isolated from each other for a long time. Therefore, it seems probable that Yellow Witlow-grass in Gower is a native, relic population that was once part of a post glacial arctic-alpine flora which has survived to this day, refuged on the south Gower cliffs.

Native