Sunday 2 November 2014

Glamorgan's smallest tetrad? (and Tortula query)

Yes, I know all tetrads are the same size, but in terms of land area ST16C must be one of, if not the, smallest in the county. It contains the very tip of Friars Point at Barry Island -  probably no more than 300 square metres of dry land above the inter-tidal.

I was down on the beach at Barry Island with the family yesterday so decided to take a quick look, given the lack of any previous records. Irritatingly I'd forgotten my phone/GPS so wasn't sure exactly where this tetrad started, and so took a cautious approach and only looked for bryos right at the point. Looking at the map when I got home, there was a bit more land in ST16C than I realised - so I'll have to have another look next time I'm there.

The samples I grabbed comprised only two species, both from thin soil among the limestone rocks: Tortella flavovirens and a Tortula (I think) which has me puzzled. Photos below.





Initially I thought this was T. modica but the cells are at least moderately papillose, the margins aren't obviously recurved and the leaf tip is a bit toothed. The latter character made me think it might be Hennediella but I think the seta is too short (only about 4mm). It doesn't seem to fit any of the other Tortula species very well. Any suggestions?

Thanks
George
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5 comments:

  1. GMT2 November 2014 at 22:39

    Or perhaps, given the habitat, T. viridifolia is more likely, though the hair points seem very short for that.

    Also had a good contender for Brachthecium glareousum further north on the same headland.

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  2. Barry Stewart3 November 2014 at 08:36

    That really is a tiny bit of land! Hennediella seems a reasonable possibility to me, but as you say setae are short - when I've seen it in fruit, they are usually lots of fruit. In summary I'm not sure, so another one for Sam sorry.

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  3. Charles Hipkin3 November 2014 at 18:30

    The toothed leaves eliminate the other Pottia types. The seta lengths are more or less in the range for H. heimii and the leaves look dead right for H. heimii.

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  4. sambbryo3 November 2014 at 20:12

    I agree with Charles. Another pointer to H heimii is that the capsule lid has remained on one capsule because of the persistent columella. Very few Glam records of that species though.

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  5. GMT3 November 2014 at 22:35

    Thanks all. Apart from not being able to see the columella itself, I was also slightly put off H. heimii as the habitat seemed a bit exposed and would be heavily salt washed, but I guess with the toothed leaf tips and persistent capsule lid it must be that.

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