Monday, 15 January 2018

Days in the Black Mountains - 2 Rhos Dirion & Nant Uchaf

A glorious Day 2 in the Black Mountains started and ended with low cloud, but there was bright sunshine in the middle of the day.  I started at Gospel Pass and walked westwards to the crags east of Lord Hereford's Knob.  These and the other north-facing crags have tempted me for ages, so it was exciting finally to visit them.  These first crags were relatively mundane ORS outcrops with base-enrichment: highlights included constant Seligeria recurvata, frequent Orthothecium intricatum, and scattered patches of Lophozia incisa, Bartramia ithyphylla, Pohlia crudaScapania aspera (dorsal branching) and Schistidium strictum.  Surprise find of the morning was an extensive colony of Zygodon viridissimus var. viridissimus on ORS at 550m altitude, which beats the Atlas altitude record.

Once the cloud had lifted, I headed over the top of the Knob to an area of base-rich flushes at SO223347, which held Philonotis calcarea, Plagiomnium ellipticum and some excellent female Riccardia incurvata.  My initial plan had been to stick to the ridges, but the unexplored headwaters of the Nant Bwch and Nant Uchaf drew me in.  A Short-eared Owl flew up from Molinia as I walked down into the valley, and I found myself in a wonderful area of scattered trees, tufaceous flushes, frozen waterfalls and ORS boulders.  The bryophyte flora didn't live up to my hopes (I cannot believe there was no Haplomitrium for example), but notable finds included Sphagnum quinquefarium, Leiocolea collaris, Preissia quadrata, Drepanocladus revolvens ssScapania scandica and Hyocomium armoricum.

Returning to the tops, I looked at dull blanket bog at 700m altitude on Twyn Talycefn - a single mound of Racomitrium lanuginosum was the highlight - and at the same altitude on Rhos Dirion.  The most remarkable find of the day was the nitrophilous Orthotrichum diaphanum on the Rhos Dirion trig point, at 713m altitude which beats the Atlas record by >150m {I don't want to think about its N source up there}.  For a brief moment the clouds were below me, and I looked west across a sea of cloud to the 'island' of Pen-y-fan.

Looking down from the top, it was obvious that the uppermost crags of Pen Rhos Dirion (700m altitude) hadn't thawed out for weeks.  They were surely the place for something rare... a relatively quick search of a few 10s of metres of the upper crag produced Grimmia torquata new for the Black Mountains, Brachydontium trichodes and Plagiobryum zieri, none of which had been seen on the morning's lower crags.  The big lower outcrops of the Pen Rhos Dirion crag await a return visit, and are likely to be base-rich and interesting.  Perhaps Graham will accompany me for that one...


  1. I'll have to remind myself what we have seen previously in Black Mountains .... Certainly Calypogeia azurea sticks in my mind. Will have to hope the snow doesn't stay around too long.

  2. This would make a good (if slightly obscure) pub quiz question: What do Zygodon viridissimus and Silurian moth have in common? They share a British altitude record on Lord Hereford's Knob.

  3. Not sure many would get the answer to that one. May be more suitable for a recorders forum!