Just a few more pics...
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| exothecial cells |
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| large adaxial cells in costa |
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| large adaxial cells in costa |
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| cells towards leaf base |
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| cells towards leaf base |
Wednesday, 10 December 2014
Schistidium query 2
There were just a couple of tufts of this growing on a sandstone rock in a small lowland stream near Gorseinon. I first suspected it might be rivulare, but am now thinking possibly apocarpum without a hyaline apex? Shoots turned to one side.
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The capsules look rather wide for S apocarpum and I'd expect at least the bracts to have hairpoints. I suspect it's S rivulare. I'll have a think about whether there are any other characters.
ReplyDeleteSpore size may help and you've got capsules. If they are 15 microns or less it rules out rivulare. If they are 16 or greater, at least that points to rivulare.
ReplyDeleteI see more rivulare than apacarpum in those sorts of habitats , especially where submergence is frequent. S. apocarpum looks neater in appearance to me.
I'm not very familiar with variation in either species so thanks for the help - I'll look at some spores and let you know, hopefully they'll be developed enough
ReplyDeleteSpores mostly 12-13 microns
ReplyDeleteSounds like apocarpum. What do you think Sam?
ReplyDeleteIf it is, it's a useful lesson for us.
Capsules still not mature which might explain spore size?
ReplyDeleteUnripe spores don't count!
ReplyDeleteCells in basal quarter of leaf should be non sinuose in rivulare and sinuose in apocarpum. Cross section of costa just up from leaf base should have differentiated larger adaxial cells in rivulare and should be uniform in apocarpum. Exothecial cells thick walled and with trigones in rivulare and thinner walled in apocarpum. Lots of characters but all subtle!
ReplyDeleteThanks Sam I check these characters out...
ReplyDeleteNeither the exothecial cells nor the basal cells in the leaf are terribly convincing for either case to me, but the differentiated adaxial cells of the costa fit your description for rivulare perfectly. I'll post a few pics later.
ReplyDeleteI agree - it looks like S rivulare on costa features. The capsule widens considerably on dehiscence, so its current length is not really an indicator of S apocarpum.
ReplyDeleteThanks for the help sorting this one out. Not rare I know, but hopefully it will have been as instructive for others as it was for me.
ReplyDelete