With the kind permission of the School a group of seven visited the extensive grounds which lie between Colinton Road and the Water of Leith. Our meeting coincided with probably the only suitable day for looking at bryophytes after a very cold week and before the next storm arrives.
There were three main habitats to explore: the relatively flat parkland around the School buildings, the mature woodland that drops towards the river, and the man-made structures and paths around the School itself. We started with the trees and a concrete block immediately inside the School entrance and debated whether we had found Sciuro-hypnum populeum or Homalothecium sericeum. Some of the leaves appeared to be striate, others not, so both species may have been present in a mossy tangle. We were more definite about the Microeurhynchium pumillum that David Chamberlain had identified last week. Although generally scarce, it appears to be well established near Craiglockhart and Colinton Dells in Edinburgh.
Thankfully there was no ice to increase the difficulty of the steep descent into the woodland where the bryophytes were very different from those already seen. One area was carpeted by Diplophyllum albicans and Pseudotaxiphyllum elegans which indicate acidity, whereas the patches of “Bounce-back moss” Eurhynchium striatum indicated more neutral soil. Epiphytes were a bit disappointing, perhaps due in part to the amount of shade, but we did find some straggly Radula complanata. Warren Maguire had been focussing on liverworts and he helped us find Calypogeia arguta and Pellia epiphylla, both missed on the preparatory visit.
After looking at an Ice House just above the river we retraced our steps to re-emerge near the ruins of Colinton Castle. The remainder of our visit was spent near the School buildings. David had been looking for Tortula truncata on the preparatory visit and finally found it growing with Dicranella staphylina in a plant tub. However we were unable to rediscover the fruiting Pseudocrossidium hornschuchianum seen a week earlier. In the course of this meeting and the previous week’s preparatory visit we identified just over seventy bryophyte species in the School grounds.
Thanks to Merchiston Castle School for granting us permission for our meeting and for being so helpful and welcoming.
David Adamson January 2024