Tuesday, 20 December 2016
Well I wasn't expecting that!
Actually, to be honest I was secretly hoping that Santa might bring me some Daltonia splachnoides during one of my days in Coedydd Nedd a Mellte, but the first couple of hours today were so dull I was really shocked to see the pretty little fringed calyptrae poking out from a log covered in Scapania nemorea. The location - well up the Mellte valleyside between Sgwd Isaf Clun-gwyn and Sgwd y Pannwr - was hardly classic for Hyperoceanic species, but I'm not complaining! This is the 4th Welsh record of this UKBAP/Section 7 moss, following three on Salix in conifer plantations in Brechfa Forest, near Llyn Brianne and near Llanwonno in the Glamorgan valleys. It was new for Breconshire, although the Llyn Brianne colony was only a stone's throw into Carmarthenshire. The general theory is that this Hyperoceanic moss is a spore-vagrant from Ireland, following Colura but more ecologically demanding. Its presence in Coedydd Nedd a Mellte SAC raises the unanswerable question of how many other Hyperoceanic rarities in the SAC are relatively recent arrivals and how many are relicts; it is notable, though, that Aphanolejeunea and Drepanolejeunea are only on riverside (mostly cascade-side) trees, so even if they are recent arrivals they have found their way to classic oceanic woodland micro-niches.
This was certainly the highlight of my day in the central Mellte, but some lovely patches of Drepanolejeunea hamatifolia on a classic riverside Ash tree below Sgwd y Pannwr, new for the Mellte, came a close second.
Otherwise, the west bank of the Mellte was good but predictable: Anastrophyllum hellerianum in a few places (only on 4 or 5 trees); equally scattered Jamesoniella autumnalis (on perhaps 15 logs & trees); Cephalozia catenulata, Lophozia incisa and Odontoschisma denudatum on logs in a side valley; one small colony of Plagiochila spinulosa; and a few tufts of Colura on riverside Hazel. Abundant Zygodon rupestris with a few sporophytes was perhaps the biggest surprise, growing on trees in the mist zone of Sgwd Isaf Clun-gwyn.