Just come back from a recent trip to Shetland. I spent most of the tie on Unst, the most northerly of the Shetland Isles. One of the main reasons for going was to look at the peculiar flora found on the serpentine debris fields. The main place to see stuff is the Keen of Hamar NNR.
As well as some rare and unusual plants it has great views north towards Saxa Vord - the old RAF radar station.
A lot of the plants growing here are not particularly rare but because of the extreme environment have odd prostrate or dwarfed forms, such as
Sea Plantain:
and
Kidney Vetch:
The reasons for this are probably because of the lack of water and extreme exposure - I've never known a windless day there. In the past people thought that nickel toxicity from the serpentine could be important but they seem to have largely discounted this.
Even the orchids grow as tiny individuals:
Northern Marsh Orchid:
Early Purple Orchid:
Frog Orchid:
None of these were growing to much more than about 5-6cm tall.
Others species have a localised Northern distribution such as
Mountain Everlasting:
or
Moss Campion:
But the real stars are things like
Shetland Mouse-ear, an endemic to Unst:
Northern Rock-cress:
and
Arctic Sandwort:
There are also Adders Tongue Fern and Moonwort, Lesser Clubmoss and all the time there are Great Skuas buzzing around and Golden and Ring Plover nesting amongst the debris. All in all a fabulous place to visit.