Surprising urban wall moss

My most surprising bryo find of the winter so far has been Ptychomitrium polyphyllum growing just a stone's throw from the Butterfly Conservation Wales office in Hafod, Swansea. I first noticed a cushion of this moss growing on the sandstone coping of a sloping wall back in November, but only remembered today to take my camera along to get a few photos. I must have walked past it countless times last year before I noticed it. The moss is in the foreground of the photos below. It is close to a busy road junction and must experience pretty high levels of nitrogen pollution.

I noticed today that as well as the large fruiting cushion there is a small non-fruiting cushion nearby (on the right-hand side in the photo below left).

The associates are all mundane species: mostly Grimmia pulvinata with some Bryum capillare and a tiny amount of Tortula muralis. The rest of the wall is almost devoid of moss apart from a few scraps of G. pulvinata here and there.

I've not seen this moss in an urban situation before, but perhaps it isn't so unusual. Sam's Pembrokeshire flora mentions its persistence on imported rocks at County Hall in Haverfordwest, shwoing it can survive some pollution.

Grimmia orbicularis

Today's photograph of my samples from Coedffaldau, which clearly show the differences between Grimmia orbicularis and G. pulvinata. Below, from the same day, Lophozia bicrenata growing in an extensive mat of hepatics at Bryn-melyn sandstone quarry (SN73781134), the main associates being Solenostoma gracillimum, Diplophyllum albicans and Nardia scalaris. The distinctive leather / cedar-wood smell of my sample is remarkably strong for such a small plant, even when dry. This character, when coupled with the compact shoots with golden-brown gemmae, make field identification straight forward.

SN71K square bash

As a birthday treat, I spent the morning looking at a short section of the Afon Llynfell and stopped for quick searches on a couple of nearby coal tips. The tips weren't particularly exciting, though Ptilidium ciliare was locally frequent. Similarly, the riparian woodland of the Llynfell was unremarkable, though should return a decent total once the records are entered and tallied. However, the most interesting observation of the day was a lovely colony of Grimmia orbicularis (I've not checked the book yet, but I'm not aware of any lookalikes?) - I'm not sure what compelled me to stop, but somehow it just looked different to other Grimmia-topped walls as I was driving along Coedffaldau SN74461141. The wall was capped with a coarse concrete mix and the main associates were Schistidium crassipilum and G. pulvinata, with smaller amounts of S. apocarpum, Tortula muralis, Syntrichia montana, Bryum capillare, Orthotrichum anomalum, Homalothecium sericeum and Barbula sardoa. I didn't count the tufts, but there must be in excess of 50. Fresh tufts G. pulvinata were obviously brighter green, though older ones were quite similar to orbicularis and I wasn't sure about some of the non-fruiting intermediates.

 southern-most plants noted, the colony extending close to the end of the wall in the distance