Zygodon rupestris

The two common Zygodons, viridissimus (var. viridissimus) and conoideus are widespread and fairly common in VC41. Roy Perry described Zygodon viridissimus as a frequent epiphyte in the county (in NPT it is also found frequently on stone). In contrast Roy described Z. conoideus as rare, but probably overlooked and confused with viridissimus. Like other epiphytes it has probably increased greatly in the last few decades. Unlike Z. viridissimus it often produces capsules in early spring, which draws your attention. Zygodon rupestris wasn't listed by Roy in the county Flora, but, if our current records are sound, it looks as if it is widespread here and probably under recorded. 

Current MapMate records for Zygodon rupestris in Glamorgan

I can't remember ever seeing Z. viridissimus with capsules, but we do occasionally find rupestris in fruit which can lead to confusion with conoideus. The Atlas warns that confusion with conoideus may have led to errors in mapped records of rupestris. So it pays to check the gemmae which in my experience are always present in these 3 species and easily found if you mash up a few leaves on a slide. Zygodon conoideus usually produces lots of gemmae which are 7 or 8 cells long while the gemmae of rupestris are 4 or 5 cells long. The gemmae of Z. viridissimus are almost bullet-shaped and, uniquely, have longitudinal and transverse cell walls.

Zygodon viridissimus: bullet-shaped gemma with longitudinal and transverse cell walls; specimen epiphytic on Sitka Spruce, Pentreclwydau

Zygodon conoideus: cigar-shaped gemma with 8 cells (no longitudinal walls); specimen epiphytic on Grey Willow, Pentreclwydau

Zygodon rupestris: gemma with 5 cells (no longitudinal walls); specimen epiphytic on mature Ash, Ynysmeudwy

Tan y Darren

Yesterday I had a thoroughly enjoyable time exploring the north-facing crags and screes at the head of Cwm Dare. It was a bit of a flying visit as I had to get back for the school run, and as usual I spent too much time looking at other habitats on the walk in from the car. I did manage to have a decent look at the screes, but after that I only had an hour left to look at the sandstone crags. This gave me enough time to explore the easternmost crags, but I didn't even make it as far west as the area where filmy ferns have been recorded.

The crags didn't disappoint, despite the lack of any obvious base enrichment. There were a couple of cracking patches of fruiting Diphyscium foliosum in rock crevices (photo below - left), a few capsules of Pohlia elongata protruding from under an overhang (photo below - right), a small patch of Cynodontium bruntonii, quite a lot of Polytrichastrum alpinum (tbc), as well as Bartramia pomiformis and Fir Clubmoss.

The screes held abundant cushions of Andreaea rothii (ssp falcata) (photo below - right) and I found a single cushion of the scarcer A. rupestris (photo below - left, though I'm kicking myself I didn't bring back a shoot to check for the similar-looking rare species). Although the rocks were acidic, the small stream which I followed up the hill from the cwm had signs of base enrichment with plenty of Ctenidium molluscum and a little Palustriella commutata. So far my list for SN9601 is 58 taxa, but I still have samples to sort through...

Fifty five taxa were recorded on the walk in through SN9602, including Climacium dendroides on colliery spoil and Riccardia palmata on a stump in wet alder woodland.

It's definitely an area which needs another visit!

Mellte bits and pieces

Also seen during yesterday's visit to the valley Plagiochila killarniensis (bifaria) in association with Bartramia pomiformis by the cliff path above Sgwd Clun Gwyn Isaf.

Barbilophozia attenuata and Zygodon rupestris on oak, plus Sanionia uncinata on a log below Sgwd y Pannwr.

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.

Andreaea rupestris var. rupestris in RCT

Hilary and I spent an hour in the vicinity of the Ton Pentre overlook (SS939945) near Graig Fach, on a cursory trip to RCT yesterday afternoon. Two under-recorded tetrads (SS99H and SS99M) can be accessed within walking distance here and despite the bitterly cold windy conditions we managed to get numbers up to the albeit  modest totals of 39 and 21 respectively.

Graig Fach

A crippling view of a 'ringtail' hen harrier below the overlook was one of the high points of the day. The other was finding Andreaea rupestris on a number of sandstone slabs in the sheep-grazed moorland.

The leaves of Andreaea rupestris are somewhat falcate-secund with a sheathing base.

Unlike A. rothii, the leaves of A.rupestris don't have a costa and unlike A. mutabilis the basal marginal cells are rectangular. 

Basal cells of leaf

The prominent papillae on the abaxial side of the leaf are a feature of A. rupestris.

Confusion with A. mutabilis (absent from South Wales) is possible, but the leaves of that species lack a sheathing base, have a distinct patch of yellow cells near the base and have basal, marginal cells that are more or less circular (isodiametric). Andreaea alpina is usually a much bigger plant, with leaves that are a different shape, with sinuose basal cells, denticulate basal margins and lack prominent papillae on the abaxial side. 

 A. rupestris is much less common than A. rothii  in South Wales. For example, there were only 3 previous records in the Mapamate database for VC41, all from the vicinity of Craig y Llyn and only one of those (courtesy of  SDSB, BS and GMT from their Craig y Llyn trip last autumn) is recent. However there's a lot more habitat like this to explore in upland Glamorgan, particularly in RCT and Bridgend, so I think we'll be able to put a few more dots on the map in the near future. Among the other mostly unremarkable species we recorded were Racomitrium fasciculare (which is abundant here) and Ptychomitrium polyphyllum - typical species of exposed, acid rock on our moorlands.