Fog and Fungi

A while back I posted about threats to the future of the Bishop of Durham's deer park at Auckland Park, in Bishop Auckland in County Durham. Thankfully these seem to have abated, much to the relief of all those who love the place. It's one of our favourite Sunday morning walks - even in the fog.

The park is at its best in autumn ....

.... especially when fog adds a touch of liquid magic to the spiders' webs.

I think it was Oliver Rackham, the noted tree and woodland expert, who once remarked that the only thing more useful to wildlife than a live tree was a dead tree. He was referring to the vast range of organisms - invertebrates, fungi, etc. - that live in or on the dead wood during a tree's protracted afterlife. Whoever manages the park at Bishop Auckland leaves plenty of dead wood for the benefit of organisms that thrive on it - like these tiers of bracket fungi (Ganoderma sp. I think) in the hollow trunk of this dead beech.

Some of the living beeches are under attack by honey fungus and their days are numbered - but there are also plenty of healthy trees and some replanting.

The stumps of old sweet chestnuts host these developing puffballs.

Sycamore, with the black spots of Rhytisma acerinum on the leaf blade.

Some of the living trees have magnificent rings of toadstools around their bases - I guess that these are a mycorrhizal species, that exist in a mutually beneficial association with the trees.

Not sure what these are, on a decaying beech stump. During the prolonged afterlife of the dead trees a whole succession of toadstools appear, some for just a few days.

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...