Tags

, , , ,

The Bird’s-nest orchid is quite a little gem of a flower, and at the outset I want to thank a Forest of Dean naturalist Frank D Williams who put me on to this flower and helped me find it.

This specimen was growing in the vicinity of the site Point Quarry in the Forest of Dean which is a bit off piste for this species. You will note that it has a single greenfly on the top of the spike which coincidentally the Fly Orchid which I photographed yesterday also had. I wonder if I should adopt this greenfly feature as a sort of trademark rather like the carpenter who always has a little carved mouse on his works…. maybe not.

Anyway the first thing to note about this orchid is the colour or lack of it, in particular no green/chlorophyll. So in order to survive it has a relationship with a fungus. This is quite complex, I will attempt to explain.

The fungus involved is called Sebacina and this fungus has a symbiotic relationship with certain trees often Beech. The fungus combines with the trees roots forming a mycorrhizal relationship. In this the fungus derives benefit in the form of sugars and other complex nutrients from the tree. The tree benefits from the fungus in that the fine threads of the fungus penetrate the soil and increase the capacity of the trees roots to absorb minerals from the soil.  Many trees have a similar relationship with different fungi. Now what the Bird’s-nest Orchid does is to sort of gatecrash this partnership and its roots also combine with the mycorrhiza on the trees roots and it also takes in nutrients and water from the tree, but it does not give anything back in return. This makes it a parasite.

You can see in this little photo a rudimentary leaf which is just a buff yellow colour as is the stalk.  In fact Bird’s-nest Orchids do have a very small amount of chlorophyll, but not enough to give it any sort of green colour and also not enough to carry out photosynthesis and to produce sugars. Most orchids have a symbiotic relationship with soil fungi but this one has taken it a stage further and become totally parasitic.

 

I said it was growing a  bit off piste and by this I mean it is not often seen in the central area of the Forest of Dean. Frank D Williams says that this  was the first time he had ever seen one growing in this part of Gloucestershire. Reference to the online atlas of British and Irish Flora tells us that the preferred pH for this species is 7 or neutral. Now much of the Forest of Dean is acidic so that is probably why it is rarely seen here. Possibly the reason this specimen was growing here is because the cycle path close to where it was located had been made up with limestone gravel.

The afore mentioned atlas does show that there are records for this orchid along the Wye valley north of Monmouth and in Symonds Yat area. Indeed it is found throughout the UK but has declined recently, only the blue dots represent recent observations.

This slideshow requires JavaScript.

You may be wondering why it is called Birds Nest orchid, well this is because were you to dig it up, which of course would be totally illegal, then you would find the roots are matted together and somewhat reminiscent of a birds nest.   Incidentally the word orchid comes from the Greek word orkhis meaning testicles and this is because some orchids have swollen roots which resemble a pair of testicles!!.

To check out other wildflowers found in the woods of the Wye valley and Ninewells wood click Woodland Wildflowers of the Wye valley and Monmouthshire.

mm

Advertisements