Monday, 20 October 2014

Schistidium query

On Friday I collected this Schistidium from a large concrete block in the flood zone of the River Taff, in Cardiff. At first I thought it was rivulare but a few (c. 10%) of the leaves have a short hair point - see photo 3 below - so I presume this must be apocarpum, though I'd appreciate confirmation. The old capsule in the second photo looks a bit shorter than that illustrated for apocarpum in Smith, but I'm guessing this is just due to variation within the species.

I hope one of you is able to confirm anyway!





Thanks
George
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6 comments:

  1. Barry Stewart21 October 2014 at 08:57

    Definitely one for Sam to look at - very short capsule

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  2. sambbryo21 October 2014 at 20:01

    It's neither of the above: that is Schistidium platyphyllum! The very broad leaves, with convex backs rather than a sharp keel are typical, as are the short capsules. Critically, though, the tiny hairpoint is characteristic of S platyphyllum despite Smith's Flora saying that hairpoints are absent from this species and S rivulare. Blom's Schistidium monograph states that hairpoints are usually present, and I have found them on every British specimen of S platyphyllum I have examined.

    I was slightly surprised to find that there are 4 previous VC41 records of this species, all mine: one from 2002 and three from 2011. Cwm Du Pontardawe, Cwm Afan Cynonville, Clydach Vale Country Park and Dinas Isaf Ind Est. Three were on rocks in streams and the fourth was on damp tarmac. This is still officially a Nat Scarce species, but it is clearly under-recorded in many parts of Britain.

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  3. Barry Stewart21 October 2014 at 21:14

    The sync file I received from Charles & Hilary today also has 6 records of this species. in new squares.

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  4. GMT21 October 2014 at 21:49

    Excellent, thanks Sam. I was put off platyphyllum not only by the hairpoints but also the fact that the capsules were well concealed by long surrounding leaves - but I think Smith does suggest that the latter character is not necessarily reliable.

    Another one to look for on my Taff riverbank surveys.

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  5. GMT21 October 2014 at 22:45

    In hindsight, I think the capsules were only concealed because they were immature.

    I should have read your account in the field guide first, then I'd have known about the hair points!

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  6. sambbryo22 October 2014 at 19:00

    You are right: the capsules look relatively narrow and hidden because they are young.

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