Tuesday, 17 January 2017

Another rare Orthotrichum in a mundane place

I had a training course at the Coldra Roundabout on the NE side of Newport today, and surprisingly light traffic meant I arrived with half an hour to spare.  I popped up to Langstone Church to make some records in this blank tetrad, and found 30+ miscellaneous things.  A quick wander along the adjacent lane produced a few epiphytes, including an Orthotrichum that was immediately obvious as one of the rare(r) ones.  Its pale, hairless calyptrae with orange tips were visible from a distance, and the fact the capsules were already expanded (and the calyptrae very short) contrasted with nearby O. tenellum and O. affine.

I didn't have my camera with me, and grabbed this photo whilst cooking supper
(that's a sliced spring onion in the background)

Following additional microscope work this morning, I am pretty confident that this is O. pumilum sensu stricto rather than O. pallens or O. schimperi.  The only old capsules are rather decrepit, but one has an exostome remaining and its split teeth combine with broadly exposed stomata, and the capsule tapering at the base to suggest it isn't O. schimperi, whilst the leaves are relatively ovoid rather than broad-based and tapering, and that indicates O. pumilum rather than O. pallens.  The relatively immersed capsules are also more characteristic of O. pumilum not O. pallens (compare it with the Flintshire O. pallens from last year.

The short, hairless, orange-tipped calyptra and tapering capsule base

Split exostome teeth and relatively exposed cryptopore stomata

Ovate leaves (not broad based and long-tapering), and remarkably blunt perichaetial leaves

It is pretty amazing that this third, rarest British member of this species complex has joined O. pallens (Dingestow) and O. schimperi (Abergavenny) on the VC35 list, and is surely evidence that these species are widespread across the country but are only occasionally being spotted.

The site - consummate mundanity!


  1. Inspired by your discovery I took Alfie for a walk to an area with mundane habitats this lunchtime and found lots of mundane species! Fabulous find Sam. Looking forward to hearing the outcome.
    BTW, any news from Des yet about the Pentyrch Weissia?

  2. It does look reassuringly different - though the fact that none of the rest of us are finding these unusual Orthotrichums suggests we must be overlooking them (unless they have a more eastern distribution in Wales).

  3. I never managed to find one in Carmarthenshire, so I think they are relatively eastern (Orthotrichum obtusifolium in Aberystwyth excepted). They should be in the Cardiff area though, George!

  4. Yes indeed, I must keep checking those flailed hedges!

  5. Nice work Sam. I can say with confidence that there is far more sliced spring onion than Orthotrichum pumilum in NPT, but I'll keep an eye open for it.