Monday, 23 October 2017

Orchids under the microscope

There was a time, when we lived on Skye, that I would be out and about in any weather.  Living down south I have got soft.  Because it was windy and wet at the weekend I spent time indoors dealing with the mass of photographs and information I gathered on orchids over the summer months.   I am interested in whether they can be reliably identified when not in flower, and I have concentrated on the edges and tips of leaves typically under x100 magnification, leaf venation, whether there are stomata before moving on to seeds (x100 magnification and seed pods.  The leaf characteristics I have compared to the descriptions in Poland and Clement (The Vegetative Guide to the British Flora), getting to grips with crenate and papillose margins.

I have summarised these in a PowerPoint files and there are some interesting differences.  For example P&C use habitat to differentiate between the three Fragrant orchids.   It works a lot of the time but not always; yet I think there are some subtle differences in the leaf characteristics - occasional stomata or not, edge characteristics and probably seed size (or more particulary the ratio of length to width).  This is an example of the presentation for one of the fragrants - chalk fragrant (Gymnadenia conopsea)

I collected data for around 30 species out of the total of 53 (?) in the UK and have so far summarised around a half.   Obviously I avoided the Schedule 8 plants and others that are rather rare and you would not stumble across them unless you were purposefully looking for them in a known location. One weakness though is that I have the very smallest of sample sizes for each but I am hoping next year to rig up something that can take at up to x60 magnification in the field.

Quite what I do with the work when completed, I am not yet sure!

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