Wednesday, 10 February 2016

On Headless Hill

I love a good coincidence... This morning, Barry phoned to ask me about bryophytes and Killarney Fern gametophyte in a ravine in Carmarthenshire; at lunchtime I had a wander on Headless Hill (in the Welsh bit of the Forest of Dean) and stumbled across a large patch of Killarney Fern!  I'm sure I would have spotted it regardless of having it in my mind, as it covered nearly 150x30cm of the overhanging side of a large conglomerate block.  I usually find the gametophyte in slightly more humid localities, but it seems less desiccation-sensitive than the very rare sporophyte stage.  This part of Headless Hill was coniferised a few decades ago and the Trichomanes rock is now under a mature canopy of conifers (I think they are Fir).

Nearby were several well-rotted Oak/Beech stumps on which grew Leucobryum juniperoideum, Dicranum scoparium and a small tuft of a very curly-leaved Dicranoid moss that I had high hopes for.  Sure enough this turned out to be the long-awaited first VC35 record of Dicranum montanum, with very mamillose leaf cells and denticulate margins.  The straight-leaved D. tauricum is relatively widespread in the V-c, but for some reason the ecologically similar D. montanum remains extremely scarce in Wales.


  1. What would you like me to ring you about tomorrow then!
    Some terrific finds there Sam in what looks like a fairly bland looking site in your habitat shot - clearly initial appearances can be deceptive.
    I know for definite that I've encountered the Trichomanes gametophyte in West Glamorgan, on more than one occasion, but have dismissed it as it wasn't in my head (even though I know it). Unfortunately I can't remember where, but hopefully I'll be more switched on in future.

  2. Fascinating. Excuse my ignorance but how is the gametophyte stage of Killarney Fern separated from that of the filmy ferns?

  3. It Is so easy to pass it over as protonema or algal filaments, and it is probably much more widespread in our valleys than we think. But I wouldn't have thought of looking for it in a conifer plantation. It grows really slowly, so a patch like that has probably been there a long time. I wonder if it was on that boulder before the conifers were planted, or has it colonised since? The gametophyte does not require hyperoceanic conditions (it has been found in Poland!) and produces gemmae, which give it a dispersal mechanism.

  4. The gametophytes of Hymenophyllum have a branched, thalloid structure - a bit like Riccardia. Those of Trichomanes are more filamentous like colonies of the alga Cladophora.