Showing posts with label Birch boletus. Show all posts
Showing posts with label Birch boletus. Show all posts

Thursday, August 4, 2011

Teesdale


Today's Guardian Country Diary describes a walk from Forest-in-Teesdale to Winch Bridge near Bowlees, along a popular stretch of the Pennine Way on the south bank of the river Tees. The 'forest' in question is the location of the juniper forest that covers much of the fellside south of High Force waterfall. It's full of wonderfully gnarled, wind-pruned trees that have a fragrance of gin if you crush their foliage between finger and thrumb.


A little further down the hill there's a sweeter kind of fragrance, when you come to the Sphagnum bog, which I guess covers about an acre - and last week was full of scented bog asphodels at the peak of flowering.
 Vast numbers of these flowers were in bloom - a better display than I have ever seen before. Teesdale is rightly famous for its rare spring gentians, but in summer the asphodels are a stunning spectacle too.


The Latin name for the plant is Narthecium ossifragum, alluding to the fact that animals were once believed to develop brittle bones if they grazed on this plant - ossifragum means 'bone breaking'. The low calcium levels in these boggy soils are a far more likely cause of any skeletal problems in grazing animals.



Further down the path the meadows beside the river are full of greater burnet .....



.... and meadowsweet, while on the rocky islands in the river ...


... the rather rare shrubby cinquefoil is in bloom ....


.... with its egg yolk-yellow flowers. In winter, when the river rises (especially after rapid snow-melt up on the fells) these shrubs are completely submerged but their roots penetrate deep into the fissures in the rocks, anchoring them in the current.


Some of the best floral displays are in the pastures near Winch bridge, full of betony ....


... and devil's bit scabious (click for a larger image, to see this more clearly).


All of these flowers are a major attraction for butterflies, like this newly-minted female common blue.


The appearance of these fine Boletus toadstools were a reminder that autumn is on the horizon.

The continuity of the wonderful flora in the pastures along this stretch of Teesdale really depends on carefully managed grazing, and the quote from a  farmer inscribed under Keith Alexander's scultures describes what would happen if the grazing stopped: "It reverts to scrub. When it's gone, it's lost".

Sunday, October 17, 2010

Birch Bolete

We found this fine specimen of a birch bolete Leccinum scabrum (and numerous others like it) amongst the silver birches on the edge of the golf course at Wylam beside the River Tyne yesterday. This bolete is always found near birch trees because its underground hyphae form a mutually beneficial relationship - a mycorrhizal association - with the roots of the tree. The fungus helps the tree absorb essential minerals like phosphorus from the soil in exchange for some of the sugars that the tree manufactures.
What I find most remarkable about toadstools is the way in which that mass of diaphenous, microscopically fine underground hyphae come together to form these wonderful three-dimensional structures. How do all those simple threads communicate and collaborate to form the stipe, the cap and - most remarkably of all - all those pores through which the spores are shed? Where does the control centre for this self-assembly process lie? Botany text books can describe with great precison how plants control their development via highly organised growing points (meristems) to produce roots, shoots, bramches, flowers and leaves but the way in which toadstools are built is much less well understood.


The gills under a toadstool's cap (or in this case the pores) must always remain perfectly parallel to the force of gravity if the spores that line them are to drop down and escape into the airstream. Displace a toadstool from the vertical and the gills will realign with gravity very quickly. The process is slower in polypores like this (and they have stouter stipes to keep them vertical) but they still adjust their growth to realign vertically.

It seems to me that a complex toadstool is one of evolution's most amazing, least celebrated, and poorly understood achievements...