Dwarf willow (Salix herbacea)
Mike Raine (July)
I posted Dwarf willow, also known as Least willow on this enviro diary a couple of years ago (May 2007) and this week passed by the same spot, near the summit of Y Garn, to see it again. I was surprised and confused to see it covered in what looked like red berries. So I put some work in to check my identification and remained confused!
Fortunately here at Plas y Brenin we have a good relationship with Dr. Barbara Jones, seed plant expert at CCW, she also a climber. I sent my photograph to Barbara and explained my confusion. Ha yes! She replied a problem she had observed people encounter before. The red 'berries' are actually the gall of a sawfly - an arctic species and in Britain its only host plant is Salix herbacea, so mystery solved. Barbara and her team have recently done some studies on the extent of Dwarf willow to ascertain its current status so it can be monitored, being confined to the highest summits of the Carneddau and the Glyderau it could easily suffer adverse affects with the onset of climate change.
So watch out for this miniature 'tree' and please, tread lightly