Didymodon icmadophilus in the Neath Valley

I've not yet checked my specimen under the microscope, but what I've been calling D. icmadophilus (as recommended by Tom Blockeel) was present in good quantity on wavy concrete-block paving at Aberpergwm.  I'm not quite sure what is happening taxonomically with acutus and icmadophilus, as the map on the NBN appears to show records for these taxa amalgamated under the latter name.  If any anyone can shed any light on what's going on I'd be grateful, just so I can enter my records under the correct name.  D. acutus at Merthyr Mawr to me looks quite different to D. icmadophilus I've seen at anthropogenic sites in West Glamorgan.

For ref,  the list of associates on the blockwork was as follows:

Barbula convoluta var. convoluta Barbula convoluta var. sardoa Barbula unguiculata Bryoerythrophyllum ferruginascens Bryum capillare Bryum dichotomum Bryum pallens Bryum pallescens Calliergonella cuspidata Cephaloziella cf. hampeana Ceratodon purpureus Dicranella varia Didymodon cf. australasiae Didymodon fallax Didymodon ferrugineus Didymodon icmadophilus Didymodon insulanus Encalypta streptocarpa Hypnum cupressiforme var. cupressiforme Pseudocrossidium hornschuchianum Trichostomum crispulum

That Didymodon!

I thought it was worth bringing this to the top again, as there's been an update bringing us a little closer to the identity of this moss, as discussed in the comments ...

After a bit of searching, I can't help feeling the material I've seen recently on base-rich coal spoil at Grovesend and concrete bases at Mynydd Lliw must be the poorly described D. validus referred to in the D. acutus entry in the new atlas. The taxon is reasonably well illustrated on the Swiss Bryophyte website as D. rigidulus var. validus. The photographs here should provide a reference against which any similar material encountered can be compared, so we can at least record it consistently until the taxonomy is resolved. The ultra-pointy leaf tip and broad base seems pretty diagnostic, especially when coupled with the darkish brown appearance. Sam, I'll send you some material for your opinion / reference. Did you say Des was doing some work on this group? If so would he be interested in a sample?

more odd moss on spoil

Today's lunchtime outing with Alfie was to another spoil site just up the road at Grovesend (SN597007). There were no odd-looking Fissidens, but the odd-looking Didymodon I reported last November (see here)[confirmed as icmadophilus], growing on concrete bases not far from this site, was again locally abundant. The 'scope pic shows it alongside fallax and note the adaxial costal cells are predominantly square. The substrate this time was seasonally inundated, fine black spoil - other species present where it occurred would suggest mildly basic conditions. I think previously we cautiously concluded rigidulus provided the best fit, though the outcome was not completely satisfactory. I'll send a sample to Sam to see if can pin it down, but opinions are always welcome. The only other oddities were Homalothecium lutescens growing as an epiphyte on a Hawthorn trunk and what looked like a sterile, flat-leaved Weissia with the same habit as controversa var. densifolia? Other general interest was provided by male plants of Didymodon fallax (photo below) and some nice fruiting patches of Cephaloziella divaricata (bottom photo).