Sunday, 24 May 2015

Bryum query

Probably a title you all dread!

I was doing fieldwork on the northern slopes of Mynydd y Gaer (SN9486) on Friday, and noted a few bryos as I went along. Most were very commonplace species as would be expected on an acidic bracken slope, but the frequent ant hills were a bit more interesting with occasional Ptilidium ciliare, Campylopus pyriformis and the Bryum shown below.

These small reddish plants were growing mixed with C. pyriformis. After digging around I did find a few rhizoidal tubers, which were the deep red-brown colour suggested by the final photo. The rhizoids themselves were brown and papillose.

Rhizoidal tuber placed on leaf to give indication of size
Cells somewhat incrassate. Leaves bordered with recurved margins.

Given the dry acidic habitat, I wondered if this could be B. bornholmense, but I'm probably way off the mark. Any suggestions welcome, thanks.



  1. Bryum rubens vs bornholmense is a difficult ID, covered about 10 years ago by Alan Crundwell in Journal of Bryology (a backissue I've now packed up for moving) following previous confusion. The bordered leaf and relatively broad cells suggest your Bryum is one or other of them, rather than B subapiculatum. From memory, the difference lies in mean width of cells on the tuber, prominence of tuber cell walls, and colour of tubers: the specimens of B bornholmense I have seen (including in Glamorgan) had strikingly honey-coloured tubers although I believe it can have red ones. I would err towards B rubens therefore.

  2. Thanks very much Sam. I looked up the paper online, Crundwell & Whitehouse 2001, but it is not open access so I can only see the abstract (unless I pay £16). I'll record it as B rubens but will hang onto the specimen.