II. With pores or tubes beneath caps (Polyporei).
III. With spines or teeth beneath the cap or branches (Hydnei).
IV. Where the spore-bearing surface beneath the cap is even, smooth, or slightly wrinkled (Thelephorei).
Section B is divided into two classes:
I. Plants club-shaped and simple, or bush-like and branched (Clavariei).
II. Plants gelatinous and irregular (Tremellinei).
SECTION A.
Class I. Key to Gill-bearing Mushrooms (Agarics).
| [1.] | Plants fleshy, soon decaying, | [2.] |
| Plants leathery, woody, persistent, | [12.] | |
| [2.] | Juice milky, white, or colored, | Lactarius. |
| Juice watery, | [3.] | |
| [3.] | Stem central, or nearly so, | [4.] |
| Stem lateral, eccentric or wanting, | [11.] | |
| [4.] | Spores white, | [5.] |
| Spores rosy, pink or salmon color, | [15.] | |
| Spores yellowish-brown, ochre color, | [17.] | |
| Spores dark brown, | [21.] | |
| Spores black, | [24.] | |
| [5.] | With volva and ring, | Amanita. |
| Volva and no ring, | Amanita (sub-genus Amanitopsis). | |
| Ring and no volva, | [6.] | |
| No ring and no volva, | [7.] | |
| [6.] | Gills free, ring movable, pileus scaly, | Lepiota. |
| Gills adnate, pileus generally smooth, | Armillaria. | |
| [7.] | Gills thin, edge acute, | [8.] |
| Gills in the form of folds, obtuse edge, | [10.] | |
| [8.] | Gills decurrent or stem fleshy. | Clitocybe. |
| Gills sinuate, notched behind, stem fleshy, | Tricholoma. | |
| Gills adnate, not decurrent, stem cartilaginous, | Collybia. | |
| Stem fleshy, cap often bright color, | [9.] | |
| [9.] | Plants rigid, gills even, cap bright, | Russula. |
| Plants with waxy gills, | Hygrophorus. | |
| [10.] | Gills decurrent, plant terrestrial, | Cantharellus. |
| [11.] | Spores white, | Pleurotus. |
| Spores yellowish or brown, | Crepidotus. | |
| [12.] | Gills serrated on their edges, stem central or lateral, | Lentinus. |
| Gills entire, stem central, | [13.] | |
| Stem lateral or wanting, | [14.] | |
| [13.] | Gills simple, pileus dry, soon withering, then reviving when moist, | Marasmius. |
| [14.] | Gills deeply splitting, with weak hairs, | Schizophyllum. |
| Gills united by veins, plant corky, | Lenzites. | |
| [15.] | Volva, no ring, | Volvaria. |
| No volva, ring present, | Annularia. | |
| No volva, no ring, | [16.] | |
| [16.] | Gills free, rounded behind, cohering at first, | Pluteus. |
| Gills adnate or sinuate, stem fleshy, soft, waxy, cap fleshy, margin incurved, | Entoloma. | |
| Gills decurrent, stem fleshy, | Clitopilis. | |
| [17.] | Ring continuous, pileus with scales, | Pholiota. |
| Ring cobwebby or evanescent, not apparent in old specimens, | [18.] | |
| Ring wanting, | [19.] | |
| Stem with cartilaginous rind, | [21.] | |
| [18.] | Gills adnate, plants on the ground, | Cortinarius. |
| [19.] | Gills decurrent, stem fleshy, gills easily separating, | Paxillus. |
| Gills not decurrent, stem fleshy, | [20.] | |
| [20.] | Pileus fibrillose, or silky, | Inocybe. |
| Pileus smooth and sticky, | Hebeloma. | |
| [21.] | Veil remaining attached to margin of pileus, often not seen in old specimens, | Hypholoma. |
| Veil on stem as a ring, | [22.] | |
| Margin of cap incurved when young, | Naucoria. | |
| [22.] | Gills separate on the stem, | Agaricus or Psalliota. |
| Gills united with stem, | Stropharia. | |
| Gills adnate or sinuate, | [23.] | |
| [23.] | Margin of pileus incurved when young, | Psilocybe. |
| Margin of pileus always straight, | Psathyra. | |
| [24.] | Pileus of normal form, | [25.] |
| [25.] | Pileus fleshy, membranaceous or deliquescent, | [26.] |
| [26.] | Gills deliquescent—inky fluid, | Coprinus. |
| Gills not deliquescent—ring present, | Annellaria. | |
| Gills not decurrent—ring wanting, | [27.] | |
| [27.] | Pileus striate—plants small, | Psathyrella. |
| Pileus not striate, stem fleshy, margin exceeding the gills, | Panaeolus. |