As with any specialized area of study, mycology employs specialized words to convey specific meanings. While highly technical language is minimized in the keys, the user should understand the specialized terms that are used. Taking the time to do this will greatly facilitate the use of the keys and understanding of the species descriptions. The specialized terms found in the keys are defined here and, in cases where a picture is worth a thousand words, the term is illustrated as well.


annulus The ring on the stem of some mushrooms, formed by the separation of the partial veil from the margin of the cap.
asci/ascus The microscopic sac-like structures which contain ascospores; ascus (singular), asci (plural). As observed in the picture to the left, many asci contain 8 ascospores.
ascocarp   The fruiting body, cup, sporophore, fructification, mushroom, etc., which bears asci.
ascospore   The microscopic reproductive propagule formed via meiosis and formed within an ascus; fungi which form ascospores are called ascomycetes. See asci/ascus.
azonate Without concentric bands of contrasting colors. An azonate cap surface is illustrated here by Perenniporia robinophila. Note that azonate does not mean the surface is featureless or smooth. The cap pictured here is quite rough, for example, but is azonate.
basidia/basidium Microscopic, often club-shaped structures bearing basidiospores on the outside; basidium (singular), basidia (plural). In this image, two basidiospores can be observed, each perched on a peg-like structure called a sterigma. The sterigmata are attached to the underlying basidium.
basidiocarp   The fruiting body, conk, sporophore, fructification, mushroom, etc., which bears basidia.
basidiospore   The microscopic reproductive propagule formed via meiosis and borne on a basidium; fungi which form basidiospores are called basidiomycetes. See basidia/basidium.
broad   Diameter of the cap of a gilled, non-sessile mushroom. See width.
cap (pileus)   The structure that bears the hymenium of basidia. For example, in the gilled fungi the cap bears the gills underneath on which the hymenium is present. With the polypores, the brackets or shelves these fungi form are often called caps. See pileus.
central Referring to a stem attached at the center of the cap or pileus.
coniferous   In the context of this key, these are trees which bear cones and not flowers. This group includes pines, firs, spruces, and hemlock. They are known as softwood species.
context (flesh) The inner sterile hyphae of the cap or pileus; not the tubes, gills, etc. The white context (red arrows) of Polyporus squamosus is in striking contrast to the brownish context (green arrows) of Inonotus dryadeus. Note the relative thickness of tubes and context in the two species.
daedaloid With elongate and sinuous pores, forming a maze-like pattern.
deciduous   In the restricted context of these keys and descriptions, deciduous refers to trees which form flowers and shed their leaves. This group includes oaks, maples, and many other broad-leaved trees. See hardwood, as a synonym.
decurrent Gills that descend or run down the stem.
eccentric A stem not attached at the center of the cap or pileus; off-center as in the picture of the stipe of Polyporus varius.
effused   Spread out over the substrate without a regular form, no true cap or pileus is formed. See effused-reflexed.
effused-reflexed A fruit body spread out over the substrate and turned back (reflexed) at the margin to form a pileus (cap). In the pictured example of Sterium complicatum, the portion labeled number 1 is reflexed and portion labeled number 2 is effused.
fertile surface   The surface bearing the hymenium. The hymenium may cover the surface of gills or teeth or spines, or line the interior of tubes, or cover the upper surface of cup fungi.
flesh (context)   The inner sterile substance of pileus or stipe exclusive of gills, spines, tubes, etc. See context.
free Gills not attached to the stem.
fruitbody   The visible fungus structure attached to the substrate. The purpose of the fungus fruitbody is to produce spores and disperse them in the environment. This web site is a guide to fungi that form fruitbodies on wood.
gills (lamellae) Plate or knife blade-like structures on the underside of the cap, often radiating from a point. Also called lamellae. The hymenium of basidia covers the gills. In this example the gills are attached, meaning they are attached to the stem. See free.
glabrous   A surface with neither hairs or scales.
hardwood   In the context of this key, these are trees which form flowers. This group includes oaks, maples, and many other broad-leaved trees. See softwood.
hymenium   The layer of basidia or asci; it lines the inside of the tubes of polypores, it covers the surfaces of gills, spines, clubs, etc. or covers the upper surface of cups and saucers.
hypha   One of the elongated cells or filaments of the vegetative phase or in the fruit body; hyphae (plural).
KOH   A 3-5 % solution of potassium hydroxide in water; used to test for color changes.
lamella   A leaf-like plate or knife blade-like plate of tissue on the undersurface of the cap; a gill. See gill.
lamellate   Composed of lamellae or gills.
lateral A stem attached to one side of the cap or pileus.
length/long (L) In sessile forms, the projection of the pileus out or away from the substrate.
lignicolous   Fungi which utilize wood as a substrate.
mycelium   The whole mass of hyphae forming the vegetative or somatic portion of a fungus.

North American Mycological Association

NEMF   Northeast Mycological Federation
partial veil (annulus) A membrane extending from the stem to the margin of the cap and covering the gills; when it ruptures it usually leaves a ring on the stem. See annulus.
perennial Lasting for more than one year; perennial polypores show more than one layer of tubes, typically one layer for each year. The polypore in the picture has three layers of tubes.
peridiole The "eggs" in a bird's nest fungus are the peridioles. Basidiospores are formed within the peridioles.
peridium An outer layer of tissue that encloses the spore-producing tissues of certain fungi. For example, the empty "nest" of the bird's nest fungi pictured here is the peridium. So, too, is the outer wall of a puffball fungus or the sac-like "egg" out of which a stinkhorn bursts.
pileate   Having a cap or pileus.
pileus/pilei   The cap-like portion of a gilled mushroom, with or without a stem; the bracket of polypores. The pileus bears the hymenium (fertile surface) on its lower surface. See cap.
polypore   A fungus in which the lower surface of the fruiting body bears tubes that open downward as pores. The pores, or tube openings, are often conspicuous but use a hand lens before deciding there are no pores.
pores The openings of the tubes covering the lower surface of a polypore fungus.
pores per mm The number of pores that fit within the distance of one millimeter. In the illustrated example Polyporus varius, the ruler markings are 1 mm apart. This polypore has approximately 5 pores per mm. A single pore of other species can be over 1 mm in diameter.
poroid   Having pores or, in some cases, pore-like depressions formed by folds of tissue.
pubescence   Covered with short, soft, downy hairs.
reflexed   A basidiocarp turned up or back to form a cap or pileus. See effused-reflexed.
rhizomorph A strand or cord of compacted hyphae, visible to the naked eye.
serrate   A margin with teeth like a saw blade.
sessile A fruit body lacking a stem and seen to be broadly attached to the wood substrate.
setae Small spine-like structures found within the tissues or on the surfaces of certain fungi. A hand lens (or a microscope in many species) is required to see them.
sinuous (daedaloid)   Crooked, curved, or winding; of pores with curved walls. See daedaloid.
softwood   In the context of this key, these are trees which bear cones and not flowers. This group includes pines, firs, spruces, and hemlock. See hardwood.
spore print A spore print is the deposit on paper of hundreds of thousands of spores from a basidiocarp allowed to rest undisturbed on paper for a few hours. The picture shows a portion of a cap placed gill surface down on white paper. Whole caps can also be used.
Here, the cap is covered for several hours. Wax paper can also be used to cover the cap. If wax paper is used, make sure the edges are pressed down to slow the drying of the mushroom and to eliminate drafts which can interfere with the spore deposit.
After removing the cap, dark deposits of spores are observed that correspond to the spaces between the gills of the cap.
Here's a view of the gills to show how the spore print above corresponds with the pattern of the gills.
In this photograph, a white spore deposit is pictured on black paper. White paper can be used exclusively for spore prints because white spore prints can be seen on white paper.
stipe, stipitate   A fruitbody with a stem.
striate Marked with parallel or radiating lines. This picture is of the striate cap of Stereum striatum.
substrate   The substance upon or in which a fungus grows.
terrestrial   Growing on the ground. Note that some fungi included in these keys may appear terrestrial but are in reality growing on buried wood .
thick (T) In sessile forms, the distance from top to bottom at point of attachment.
tomentose   Covered with dense matted hair or wool-like pubescence.
tubes The cylindrical hollow structures typical of fungi called polypores. In this picture of Polyporus squamosus, the red arrows indicate the tubes which have been longitudinally cut open to reveal the hollow interiors. The hymenium lines the inside of each tube.
volva A cup-like or sac-like structure at the base of the stem of a fruit body. It represents the bottom portion of a membrane or universal veil that once enclosed the entire mushroom. This picture is of Amanita jacksonii which is not a wood-inhabiting species. It does, however, have a very good example of a volva.
width/wide (W) In sessile forms, the length of horizontal attachment to substrate.
zonate Marked with concentric bands of contrasting colors.


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