Key to Fungi of the Chicago Region

a variety of fungi

This key is written for the known fungi of the Chicago Region, that is north-eastern Illinois and north-western Indiana. It does not cover additional mushrooms and fungi found in other parts of these states. Disclaimer

Choose a group below to start. Groups are separated based on their shape and the kind of structure that produces the spores. Not color. Some groups are mostly restricted to growing on the ground and others to growing on wood. In this key, mushrooms are generally thought of as having a distinct stem and cap (with a top and underside) and they are also fleshy fungi (soft to firm) that are short-lived (lasting a day or a week). Mushrooms in certain groups may have a short stem or a stem attached to the side of the cap. Some gilled mushrooms don't have a stem. Additional fleshy fungi have other growth forms listed below, such as puffballs, stinkhorns, and jelly fungi. Other longer-lived fungi tend to be tougher, leathery, or hard. The fungus-like organisms that are not included in Kingdom Fungi are the slime molds (Mycetozoa) and the water molds (Oomycetes).


Key to Fungi
Key Choice
Images by Patrick Leacock unless noted. Basidium drawing by intern Dwyer Kilcollen.

Phylum Basidiomycota

The following groups of fungi have spores produced on outside of a basidium (reproductive cell).

Four spores on a club-shaped cell.
Mushroom cap with gills underneath.

Gilled mushrooms, the agarics

Cap has gills underneath. Gills may attach to the stem or run down the stem but the gills are not shallow ridges (if so, then see chanterelles below). Fleshy fungi with cap and stem. Stem may be short, lateral, or absent. Growing anywhere. If stem absent AND fungus is leathery to woody, and growing on wood, then see pored brackets below.

Drawing of gilled mushrooms.
Mushroom cap with pores underneath.

Pored mushrooms, the boletes

Cap has pores or tubes underneath. Pores can be round, angular, or radially elongated. Fleshy fungi with cap and stem. Stem may be short or off-center. Growing on the ground, rarely on rotted wood. If stem absent, then see pored brackets below.

Drawing of pored mushrooms.
Chanterelle with ridges underneath.

Chanterelles and trumpets

Cap undersurface has ridges or wrinkles or is smooth. Ridges can have cross-veins. Fleshy fungi with cap and stem. Stem may be short. Growing on the ground, rarely on rotted wood. If stem absent or very short and growing on wood, then see crust fungi below.

Drawing of chanterelles and trumpets.
Mushroom cap with spines underneath.

Toothed fungi, the hydnums

Fungi with spines or teeth that hang downward. May have a cap. May have a stem or have branches. Growing on the ground or on wood; one species on pine cones. If teeth are flattened and join together at base in a network (use hand lens), then see pored brackets below. If small and gelatinous, then see jelly fungi below.

Bracket with pores underneath.

Pored brackets, the polypores

Cap has pores underneath. Pores can be round, angular, radially elongated, or gill-like. Fungi with cap. Stem absent or present. Often growing on wood, some growing on the ground or from buried roots. If stem present and fungus not growing on wood, then fungus is tough, leathery to woody, not fleshy.

Crusts, parchment fungi

Underside smooth, wrinkled, veined, bumpy. Fungi with or without cap. Most are thin brackets or crusts. One species has split gills. One species has crinkled gill like folds. If stem present then the cap does not have gills, pores, or teeth. Often growing on wood, some growing on the ground.

Club and coral fungi

Fungi with slender stalks or club-shaped or branched, coral-like. See also earth tongues below. Often growing on the ground, some found on wood.

Gastroid fungi - puffballs, stinkhorns, bird's nest fungi, false truffles

Fungi that have spores produced within an enclosed structure. Most growing on the ground, some found on wood or wood chips. False truffles grow underground.

Jelly fungi

Fungi that have a gelatinous texture. Spores produced on surface of the jelly. Most growing on wood, some found on ground or bases of plants.

Rusts, smuts, bunts, and relatives

A few of these fungi are large and noticeable. For more information see Tree of Life Web Project: Pucciniomycotina and Ustilaginomycotina. Read about Ergot or Claviceps.

Phylum Ascomycota

The following fungi have spores produced inside an ascus (reproductive cell).

Morels, saddle fungi, and cup fungi

Fleshy to brittle cups, with or without stem. Most on the ground, a few grow on wood. Morels, false morels, and the related elfin saddles are in this group.

Earth tongues and jelly babies

Various fleshy to brittle club-shaped fungi that are ascomycetes. These are usually found in mossy or wet places. These are unbranched but can be confused with some basidiomycete club fungi.

Flask fungi

Dead man's fingers, cramp balls, and a variety of other fungi that produce spores inside tiny flask-like structures (perithecia). Most are appear like black crusts or black bumps. A few are more brightly colored. Previously called pyrenomycetes and loculomycetes.

Truffles

Tuber fungi that grow underground. Rarely found in our area. Some produce white or colored spore mats on the surface of the soil that are seen frequently. There are similar false truffles that are basidiomycetes.

Lichens and lichenized fungi

Fungi that form a symbiotic partnership with algae and cyanobacteria. Found on trees, rocks, or the ground.

Yeasts; mildews; molds, asexual fungi

These are not covered here since they are not considered macro-fungi.

Phylum Glomeromycota

Known as the arbuscular mycorrhizal fungi, these microscopic fungi form symbiotic partnerships with the roots of most plants. They form large multinucleate spores underground. For more information see Tree of Life Web Project.

Phylum Zygomycota

The bread molds and sugar molds. These fungi typically have a zygosporangium (reproductive cell). For more information see Tree of Life Web Project.

Phylum Chytridiomycota

The chytrids are fungi that typically have have zoospores (motile reproductive cells). Most are small aquatic fungi. For more information see Intro to Chytrids or the Tree of Life Web Project.

The initial development of this guide page was funded through a Chicago Wilderness grant program supported by the USDA Forest Service Northeastern Area, State and Private Forestry, and the US Fish & Wildlife Service; grants of federal monies are administered by the Illinois Conservation Foundation.