Introduction to Fungi

Introduction to fungi

Identifying features

Pic 1 General features of a combination of mushrooms.

Pic 2 Cap Shapes

  Pic 3          Gill Shapes and names

This is an introduction to fungi which will aid you to set about using techniques to help you with their identification.

The shape, colour, texture and size of the cap are all obvious identification features and are the first port of call.

The stem is also a good feature to examine with many variations of texture, ring or no ring, type of ring if present, markings and size in height and width. In this case it is always important for id reasons to pull the mushroom out by the root to examine the base as this can be a really important id feature.

Gill attachments are important in identifying mushrooms but not necessarily the best identification characteristic for reliability. A species may have several different types of gill attachments, for example adnexed, emarginate, and sinuate, even on the same mushroom. Notched is a term used to mean either sinuate or emarginated. Gills can also be interconnecting, crowded, close, broadly spaced or radiating.

Habitat, substrate and time of year are all essential clues that will help you determine your mushroom identification along with the other features already mentioned. Mushrooms grow in all environments, heathland, grassland, broadleaf woodland and amongst conifer forest, etc. but making a note of where you found them, what trees they were amongst or on will be a great help.

Spores and other microscopic features are often used for identification as they are all unique in shape and size and they come in many colours according to the type of mushroom in question. Once seen under microscope a key is used to determine which genus and species they are categorised in and then identification is established.

Picture 4, Spore prints.


What mushrooms are and their functions:

There are 1400 different mushrooms in Britain. Fungi are organisms that are not generally visible they consist of mycelium which is found underground or in various substrates i.e. dead and live wood, leaves, plants etc. Mushrooms are the fruiting bodies of fungi, they are the equivalent to the fruit of a plant and are the reproductive parts of the fungus. Spores are created within the gills and their functions are like the seeds of a flower. Our environment would not look as it does today if there were not any mushrooms present. They keep our eco system healthy and tidy and fungi form symbiotic relationships with most plants aiding their growth by keeping them fit and healthy as they search deeper and harder for water and nutrients for their hosts.

Fungi were one of the earliest forms of organisms to evolve. In the evolutionary tree of life, algae and fungi were present and formed mycorrhizal relationships, from which Lichens developed along with some of the earliest forms of plants evolving very soon after.

Mycorrhizal fungi and their associations are one of the oldest types of fungi associations. Plants as we know them today would not be here if these relationships had not been established.

Fungi have more in common with animals than plants, according to DNA structure. Mushrooms are heterotrophic like animals and are organisms that cannot synthesize their own food and are dependent on complex organic substances for nutrition.

Fungi Types

Saprotrophic – Wood decaying fungi. Decaying dead matter, within their varied natural habitats fungi usually are the primary decomposer organisms present. Many species are free-living saprobes, users of carbon fixed by other organisms, in woody substrates, soils, leaf litter, dead animals and animal exudates. The large cavities eaten out of living trees by wood-decaying fungi provide nest holes for a variety of animals.

Pathogenic - These infections come in different forms attacking live trees, these are pathogenic, parasitic and bacterial fungi. Parasitic fungi attack living trees but they slowly kill them and then go into a second saprotrophic stage, these pathogenic fungi cause white rot, brown rot or soft rot.

Bio- trophic parasite - Bio trophic parasite fungi are the exception in regard of parasites and do not kill a plant or tree, an example of this is rust fungi (Basidiomycota) and powdery mildew fungi (Ascomycota) but the health of the tree is slowly compromised.

Mycorrhizal - Symbiotic relationship. Mutually beneficial relationship between the host and fungus.

Types of wood decay

White rot - this is a simultaneous and selective rot, breaking down cellulose, hemicellulose and lignin. It can be present live trees and dead wood

White rot fungi - White rot fungi are typically associated with hardwood decay and their wood decay patterns can take on different forms. White rotted wood normally looks bleached and leaves the wood like a spongy or stringy mass, or it may appear as a selective decay or a pocket rot. White rot fungi possess both cellulolytic and lignin degrading enzymes. This gives the potential to degrade all parts of the wood in the right conditions. Species such as Honey fungus, Conifer butt rot; several others are commonly found on stumps or on the decaying major roots of trees, sulphur tuft and the "Velvet shank, a bracket fungus, Dryads saddle. Tinder hoof fungus (Formes formentarius).

Brown rot - Brown-rot fungi break down hemicellulose and cellulose. The wood shrinks, shows a brown discoloration, and cracks into roughly cubical pieces; hence the name brown rot or cubical brown rot it affects live and dead wood. Brown rot fungi are the most common in regard to attacking structural conifer wood products. A series of celluloytic enzymes are used in the degradation process by brown rot fungi, but no lignin degrading enzymes are generally present. Brown rot species found on trees are the Cauliflower fungus, Beefsteak fungus, Chicken of the woods and Dyers Maize Gill.

Soft rot - Soft-rot fungi secrete cellulase from their hyphae, an enzyme that breaks down cellulose in the wood. Soft rot fungi typically attack higher moisture, and lower lignin content wood and can create unique cavities in the wood cell wall. These enzymes create a unique pattern of decay. The soft-rot fungi have little or no effect on lignin. The fungi that cause soft rots include several Ascomycota (Spore shooters). Species include King Alfred’s cakes.

Truffles - Mycorhizzal association with many host trees, depending on species of truffle.. We have many different species here in the UK and many false truffles too.

Woodlands I feel are not encouraged and sometimes overlooked, unused, un-managed and disregarded on the South Downs perhaps because of the rare downland environment that surrounds them and the unique downland habitat that  provides for many important and rare organisms but also within this environment are the occasional pockets of ancient woodland and other types of woodland which remain and provide for an equally rare community of special importance, a truffle community! An existence which I would like to see continue and conserve through sustainable agro farming and management of woodlands with a regard to fungi and truffles.

Code of Conduct

Picking mushrooms must always be done in a sustainable manner. Do not pick all of the ones that you find, always leave some behind, especially the young specimens. This is to ensure that the remaining ones have the opportunity to fully spore for the next generation of mushrooms. Only pick what you need, there is no need to pick more than a kilo and a half per person. Take care of surrounding plants and wild flowers while picking and leave the site as you found it with as little disturbance as possible. Many animals, slugs and insects rely upon mushrooms either to feed on or lay their eggs in, providing food for the lava with most trees and plants aided by many types of mushrooms to keep fit and well. Ecological functions rely on mushrooms more than we sometimes realise. Even the pathogenic mushrooms have their role to play for an ecological balance.

Mushrooms should be cut from their stem and not pulled out by the roots unless you are uncertain of its identification. Pulling them out disturbs and damages the mycelium which if left exposed can dry out and kill the fungus. If you do have to do this cover up the hole that you have left open.

NEVER eat a mushroom until you are a 100% sure of its identification and if you are unsure always get the mushroom identified by a professional, otherwise it could have very nasty or even fatal consequences.

Picture references:

Picture 1

Picture 2

Picture 3 http://

Picture 4

Mushrooms Demystified, Pg 17, David Arora,1986, Ten Speed press Berkeley

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