Thursday, 28 September 2017

Pocket Parking again

Yesterday was the occasion of another matutinal stroll to Byfield Pocket Park but this time I had a companion - my daughter's young and inquisitive dog, Bing. (Bing as in Crosby or Byng as in Admiral John Byng? I must find out.)
The day before I'd begun by examining the Turkey Oaks hard by the Village Hall; yesterday I checked on the Arabian Medick not far away. It looks very like a clover (Trifolium) but the structure of the pods is sufficiently different to place it in a separate genus as Medicago arabica.
With a chocolate-coloured spot on each leaflet Arabian Medick is
unmistakeable. Byfield, Northants. 27 September, 2017 
With little in flower I turned my attention to the lichens on fences and tree trunks. Fascinating though they are I can never make a serious study of these organisms. (I say 'organisms' although each lichen is a symbiotic pairing of an alga and a fungus; the scientific name given to each lichen is that of the fungal component.) To begin a proper study of lichens it would eventually be necessary to purchase a range of chemicals which, when applied to a specimen, will promote a reaction showing as a colour change.

Potassium hydroxide, sodium hypochlorite, paraphenylenediamine, iodine solutions, nitric acid, lactophenol-cotton-blue and occasionally other chemicals may be called upon and may produce a yellow, red, purple, green or brown reaction when applied to a specimen. Use of these chemicals raises three problems.
1. They may be difficult to obtain (although sodium hypochlorite is easily purchased as 'Domestos').
2. Some, I suspect are quite expensive.
3. There is an element of danger attached to the use of some.

So, all in all, I am not planning to take up lichenology, even though in many cases the use of chemical reagents is unnecessary. But I still can't resist photographing examples despite the fact that Northamptonshire, with its limited range of rather bland landscapes and habitats (gravestones excepted), is probably one of the least profitable counties to explore for these curious organisms.
Lecanora carpinea is widespread on the smooth bark of trees and I believe this is the species shown here. But Lecanoras are tricky and I'm quite prepared to be told I'm wrong.

Lecanora carpinea? Probably, but I have been known to make errors
 (in their hundreds!) Byfield Pocket Park. 27 September, 2017
Less problematic is Evernia prunastri, also widespread and occurring in rough bark as well as smooth. A large percentage of trees in the pocket park bear this lichen.
Evernia prunastri in Byfield Pocket Park. 27 September, 2017
Pale oval patches with black spots  are likely to be specimens of Lecidella elaeochroma. They very much favour smooth trunks and are common on ash trees. The thallus (main body of the organism) will test orange with sodium hypochlorite, thus distinguishing it from similar species, but I happened not to be carrying a bottle of Domestos with me.
Lecidella elaeochroma - probably. Byfield Pocket Park.
27 September, 2017
It may seem strange but my canine companion was uninterested in lichens and told me so in no uncertain manner. I admit there was nothing exciting to see but if I could find a nice Usnea species. Of course she is young and there is time... Anyway, by now Bing was feeling tired [Ed: be honest - you were the weary one!] so we trudged back to the car in time to meet up with Chris.

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