27 February 2011

Yellow Whitlowgrass now flowering

The Yellow Whitlowgrass (Draba aizoides) was in flower on Pennard Castle yesterday. For those who don't already know, the South Gower cliffs are the only place this mediterranean-montane species is found in Britain and the castle is by far the easiest place to see it. A couple of hoverfly bee-mimics Eristalis pertinax were noted feeding on/pollinating the plants.
The commonest associate of the Yellow Whitlowgrass was the mediterranean-altlantic moss Neat Crisp-moss (Tortella nitida), a cushion-forming species noted all over the castle, shown here growing on mortar. Note the small plat of Yellow Whitlowgrass top right, not quite in flower.  For close ups of this rather fragile-leaved moss see http://moonmoths.blogspot.com/2011/02/mosses-on-pennard-castle.html


Charles Hipkin said...

The occurrence of Yellow Whitlow-grass (Draba aizoides) on the south Gower cliffs is remarkable. Elsewhere in Europe it is an alpine species (it doesn't occur in the Mediterranean) where it is often found above tree line in the Pyrenees, the Alps and the Carpathian Mountains. It doesn't occur in the Arctic. It is probably a relic of the tundra flora that occurred in South Wales after the last ice age. Purple Saxifrage (Saxifraga oppositifolia), which often grows with Yellow Whitlow-grass in the Alps, also has a relict distribution in South Wales (in the Brecon Beacons).

Barry Stewart said...

Thanks Charles. Interestingly the New Atlas refers to Yellow Whitlowgrass as belonging to the Mediterranean-montane element - Perhaps its biogeographical status needs reviewing?