Botanical Book at Bedtime: Part Three

Last Sunday's episode of our Botanical Book at Bedtime saw Peter Llewellyn & co looking up towards the summit, shrouded in mist and cloud, where the elusive Diapensia is said to grow, and ended with Peter's comment "Things didn't look too good..." So, what happened next?    

Treasure hunting in the Wester Ross uplands 

Part 3: The summit of Fraoch-bheinn

Diapensia lapponica
Image: P. Llewellyn

By now there were many more rocky outcrops and the soggy moors had given way to rougher ground with more sharp rocks and fewer bogs. Checking the GPS to see how high we'd climbed was quite encouraging but there was still no sign of the quartz veined bare rock on which our plant was reputed to grow.

The cloud base had moved a little higher but the summit was still looked distant, pale grey and a long way off through the mist and cloud. At this stage I was pleased to have photographed a few mountain plants because it wasn't at all certain we would find this elusive plant and still less certain that it would be in flower.

Eventually the clouds parted and sunshine came through for the first time. The party was strung out over the high hills by now and the experienced walkers plus Bridie the lurcher were likely to be the first on the scene with the botanists behind them and the photographer botanists (me) last of all. 

Diapensia lapponica
Image: P. Llewellyn

As I gathered myself for the final 100 feet or so, I could distinctly hear yelps of pleasure from those already at the top. I hoped they'd found Diapensia but it seemed too much to expect. Surely they couldn't already have found the one rock on which this very rare arctic alpine grew?

As I reached the first plateau at the top it became obvious why there was so much shouting. Clumps of Diapensia were everywhere basking in the summer sunshine. It was at its very best and in full flower. Far from being one clump on a single rock there were hundreds of cushions each with several disproportionately large, creamy yellow flowers compared with the tiny oval leaves of the plant.

It seemed too good to be true so we checked that the flowers had the three lobed fused stigmas which they did although the books didn't seem to mention the very distinctive twin lobed bright yellow anthers. It was indeed Diapensia lapponica growing on bare acid rock most of which had the shiny white crystalline quartz veins accurately described by previous expeditions.

Diapensia lapponica growing on  quartz-veined bare rock
Image: P. Llewellyn

We also wondered whether the short flowering period might be related to how easy it is to knock a whole flower from its stalk. Whole Diapensia flowers very easily fall off just like Speedwell flowers do when knocked only slightly. My camera lens inadvertently knocked quite a few flowers from their cushions.

As we looked around trying to choose the best clump to photograph, it occurred to me that this plant grew on the least nutritious piece of rock in Scotland. Later I discovered that it also grows on top of Mount Washington in the United States where wind speeds of 234 mph have been recorded. It is now believed that some of the nutrients it needs to survive are blown in by wind and trapped in the clumps. If this is true then it probably needs an exposed windy position to survive and may not be able to compete with plants growing even in poor soil. It is a sort of ground dwelling version of a sea anemone.

Kalmia procumbens
Image: P. Llewellyn

We spent some time at the top marvelling at how this famous and inaccessible plant had not only successfully colonised the three or more rocky plateaus on this single mountain ridge but seemed to love it there. As long as this habitat remains the horrible, cold, high, windy and inaccessible place with bare rock and no soil that it is, Diapensia would appear to be in no danger even though this mountain ridge is the only site in Britain.

As we studied the cushions of Diapensia lapponica (Diapensia) it became clearer why this very rare plant could be confused with Kalmia procumbens (Trailing Azalea). Both plants are found well high in hills and for most of year neither will have flowers. The leaves of Diapensia perhaps appeared a bit darker to us but otherwise were very similar to Kalmia procumbens.

Kalmia procumbens growing in the high hills
Image: P. Llewellyn

My reckoning is that there are probably over 1,000 separate Diapensia clumps on the various rocky promontories which make up the summit ridges and plateaus of this mountain. I guess that the reason why the abundance was never mentioned to us by other botanists was that so many have made the ascent only to reach the top in bad weather or after flowering and been only too glad to get back down to civilisation without doing too much exploring of the whole summit.

For me it had been one of the hardest climbs and as I looked back at the abundant flowers of this extraordinary rarity I realised I'd probably never make the ascent again. All we had to do now was re-trace our steps and contemplate some boasting to botanical friends who hadn't yet made the trip and of course, to the Inverness Naturalists".

Anyone who has ever been up a mountain will smile at "All we had to do was re-trace our steps" - or is Peter just toying with us? Was it really that straightforward? Peter is sending the final episode through in time for next Sunday's Botanical Book at Bedtime. Will it just read "Made it safely to the pub - have you noticed how good a pie and a pint taste after a day on the hill?" Or did they stumble across anything else of interest during the descent? We'll all find out next Sunday evening!