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Wednesday 1 January 2020

Schistidium rivulare vs platyphyllum

I'm trying to get to grips with Schistidiums other than S. crassipilum (being practically the only one I saw in Gloucestershire of course). Collected this on a rock in a stream in SO0522 (Cwm Cwarelli) near me, thinking it might be S. rivulare. No hairpoints and the capsules look fairly short (especially the one old one I gathered). Exothecial cells look incrassate to me and the leaf characters look OK for S. rivulare. But... the perichaetial leaves don't really overtop the capsule, and I can't see any stomata on the couple of capsules (one old and one immature) I've checked. Can anyone help?





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4 comments:

  1. Charles Hipkin1 January 2020 at 19:23

    Claire, the capsules on your plants clearly exceed the sheathing leaves, which is a key feature of Schistidium platyphyllum. Also, the habitat is right.

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  2. GMT1 January 2020 at 22:21

    I remember Sam telling me that platyphyllum often has very short hair points on some of the leaves, which are lacking in rivulare. It might be worth checking your sample again to see if you can find any short hair points?

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  3. sambbryo5 January 2020 at 20:13

    I was just about to ask whether you'd checked for very short hairpoints on the perichaetial leaves, but George got there first (thankyou!). The perichaetial leaf length certainly looks better for S platyphyllum.

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  4. claire_halpin6 January 2020 at 14:59

    Thank you all. I can't see any hairpoints on the perichaetial leaves, but are these always present? I'd be happy to say S. platyphyllum; it was mainly the exothecial cells that had me doubting it - but cell wall thickness is a pretty subjective character and this was an old capsule too.

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