Mushroom glossary A–Z — plain-English mycology terms

A

Agar

A seaweed-derived gel used in Petri dishes to grow and clean up mushroom cultures.

Annulus

The ring left on a stem where the partial veil tore away as the cap opened.

Autoclave

A pressurised steriliser; a pressure cooker is the home grower's version.

B

Basidiomycete

The big group of fungi that make spores on club-shaped cells: most gilled mushrooms belong here.

Basidium

The microscopic club-shaped cell on a gill that bears (usually four) spores.

Biological efficiency

Fresh mushroom weight divided by dry substrate weight, as a percentage. 100 % BE = 1 kg fresh per 1 kg dry.

Bulk substrate

The cheap, low-nutrient material (straw, coir, sawdust) that grain spawn is mixed into.

C

Cap

The top of the fruiting body, also called the pileus.

Casing layer

A thin, water-holding top layer that encourages pinning.

Colonisation

The stage where mycelium grows through and claims the substrate.

Contamination

Unwanted moulds or bacteria in a grow; green, black or slimy patches are the usual signs.

See also: Trichoderma · Sterile technique

Culture

A living sample of a fungus kept on agar, grain or liquid.

D

Decurrent gills

Gills that run down the stem, as on oyster mushrooms.

Dikaryon

A hypha carrying two compatible nuclei: the stage that can form mushrooms.

E

Ectomycorrhizal

Fungi that wrap tree roots and trade nutrients with them; ceps and chanterelles are examples.

Edible

Safe to eat when correctly identified and properly cooked. Never eat a wild mushroom on one ID feature.

F

FAE

Fresh air exchange: how often the air around a grow is replaced. Too little = long stems.

Field capacity

Substrate holding as much water as it can without dripping.

Flush

A wave of mushrooms fruiting at the same time. Kits typically give 2–4 flushes.

Fruiting body

The mushroom itself: the part of the fungus that makes spores.

Fruiting chamber

Any container that keeps humidity high and air fresh while mushrooms form.

G

Gills

The thin blades under the cap where spores are produced.

Grain spawn

Sterilised grain fully colonised by mycelium, used to inoculate bulk substrate.

H

Hyphae

Single threads of fungal cells; together they form mycelium.

I

Inoculation

Introducing spores, culture or spawn to a sterile or pasteurised substrate.

L

Liquid culture

Mycelium growing in sugary water, used to inoculate grain quickly.

Look-alike

A species that resembles an edible one; some are deadly. Check every ID feature.

M

Monotub

A plastic tub with holes that acts as a simple fruiting chamber.

Mycelium

The thread-like body of a fungus that grows through soil, wood or substrate.

Mycology

The study of fungi.

Mycorrhiza

A partnership between fungal threads and plant roots.

P

Pasteurisation

Heating substrate to about 60–80 °C to knock back competitors without sterilising it.

See also: Sterilisation · Bulk substrate

Pinning

The moment tiny mushroom primordia (pins) appear.

Primordia

The first tiny knots of mycelium that grow into mushrooms.

R

Relative humidity

Moisture in the air as a percentage; most mushrooms fruit at 85–95 % RH.

S

Saprotroph

A fungus that feeds on dead material such as wood or leaves; oysters and shiitake are saprotrophs.

See also: Ectomycorrhizal · Wood-rotter

Spawn

Any material colonised by mycelium and used to start a new grow.

Spawn ratio

Proportion of spawn to substrate, e.g. 1 : 4. More spawn = faster, safer colonisation.

Spawn run

Another name for the colonisation stage.

Spore print

The coloured dust left when a cap drops its spores on paper; a key ID feature.

Spores

Microscopic reproductive cells released by the gills or pores.

Squeeze test

Squeeze a handful of substrate: a few drops = field capacity; a stream = too wet.

Sterile technique

Working clean (still air, alcohol, flame) to keep contaminants out.

Sterilisation

Killing everything in a substrate, usually by pressure cooking at 121 °C.

Stipe

The stem of a mushroom.

Substrate

The material mushrooms grow on: straw, sawdust, coir, coffee grounds or grain.

See also: Bulk substrate · Field capacity

T

Trichoderma

A common green mould that out-competes mushroom mycelium.

U

Universal veil

A membrane covering a young mushroom; remnants form the volva and cap warts.

V

Volva

The cup-like sac at the base of some mushrooms, including deadly Amanitas. Always dig up the whole base.

W

Wood-rotter

A saprotroph that breaks down wood; most easy-to-grow species are wood-rotters.

Mushroom words, in plain English

A