The following compendious analytical table showing prominent characteristics of the leading genera and subgenera of the order Agaricini, according to Fries, Worthington Smith, and other botanists, which appears in Cooke's Hand Book, revised edition, will be found helpful to the collector in determining the genus to which a specimen may belong.

Order Agaricini

  1. Spores white or very slightly tinted—Leucospori
    1. 1. Plant fleshy, more or less firm, putrescent (neither deliquescent nor coriaceous)
      1. 2. Hymenophore free
        1. 3. Pileus bearing warts or patches free from the cuticle (volvate) Amanita
        2. 3. Pileus scaly, scales concrete with the cuticle (not volvate) Lepiota
      2. 2. Hymenophore confluent
        1. 4. Without cartilaginous bark
        2. 4. With cartilaginous bark
    2. 1. Plant tough, coriaceous or woody
      1. 13. Stem central.
        1. 14. Gills simple MARASMIUS
        2. 14. Gills branched XEROTUS
      2. 13. Stem lateral or wanting
        1. 15. Gills toothed LENTINUS
        2. 15. Gills not toothed PANUS
        3. 15. Gills channelled longitudinally or crisped TROGIA
        4. 15. Gills splitting longitudinally SCHIZOPHYLLUM
        5. 15. Gills anastomosing LENZITES
  2. Spores rosy or salmon color—Hyporhodii
    1. 16. Without cartilaginous bark
      1. 17. Hymenophore free
        1. 18. With a volva Volvaria
        2. 18. Without a volva
      2. 17. Hymenophore confluent, not free
        1. 20. Stem central
        2. 20. Stem lateral or absent Claudopus
    2. 16. With cartilaginous bark
      1. 22. Gills decurrent Eccilia
      2. 22. Gills not decurrent
        1. 23. Pileus torn into scales Leptonia
        2. 23. Pileus papillose, sub-campanulate.
  3. Spores brownish, sometimes rusty, reddish or yellowish brown.—Dermini.
    1. 25. Without cartilaginous bark.
      1. 26. Stem central.
        1. 27. With a ring.
        2. 27. Without a ring.
      2. 26. Stem lateral or absent Crepidotus
    2. 25. With cartilaginous bark.
      1. 33. Gills decurrent Tubaria
      2. 33. Gills not decurrent.
        1. 34. Margin of pileus at first incurved Naucoria
        2. 34. Margin of pileus always straight.
  4. Spores purple, sometimes brownish purple, dark purple, or dark brown.—Pratellæ.
    1. 36. Without cartilaginous bark.
      1. 37. Hymenophore free.
        1. 38. With a volva Chitonia
        2. 38. Without a volva Psalliota
      2. 37. Hymenophore confluent.
        1. 39. Veil normally ring shaped on the stem Stropharia
        2. 39. Veil normally adhering to the margin of the pileus Hypholoma
    2. 36. With cartilaginous bark.
      1. 40. Gills decurrent Deconica
      2. 40. Gills not decurrent.
        1. 41. Margin of pileus at first incurved Psilocybe
        2. 41. Margin of pileus at first straight Psathyra
  5. Spores black or nearly so.—Coprinarii.
    1. 42. Gills deliquescent COPRINUS
    2. 42. Gills not deliquescent.
      1. 43. Gills decurrent GOMPHIDIUS
      2. 43. Gills not decurrent.
        1. 44. Pileus striate Psathyrella
        2. 44. Pileus not striate Panæolus

In the Friesian classification which, with modifications, has prevailed for many years among mycologists, the genus Agaricus included in its subgenera the greater part of the species of the order Agaricini. The subgenera, printed in the above table in italics, were included in this genus. The genera are printed in capitals. In the Saccardian system, all the subgenera of Agaricus having been elevated to generic rank, the term Agaricus is limited to a very small group which includes the subgenus Psalliota of Fries, the species being characterized by fleshy caps, free gills, ringed stem, and dark brown or purplish brown spores. As restricted, it naturally falls into the spore series Melanosporeæ.

In the white-spored section, Leucospori, the recorded edible species occur in the following genera: Marasmius, Cantharellus, Lactarius, Russula, Hygrophorus, Collybia, Pleurotus, Clitocybe, Tricholoma, Armillaria, Lepiota, and Amanita. The plants of Marasmius are usually thin and dry, reviving with moisture. Cantharellus is characterized by the obtuseness of the edges of the lamellæ, Lactarius by the copious milky or sticky fluid which exudes from the plants when cut or bruised. Russula is closely allied to Lactarius, and the plants bear some resemblance in external appearance to those of that genus, but they are never milky, and the gills are usually rigid and brittle. In Hygrophorus the plants are moist, not very large, often bright colored, and the gills have a waxy appearance. The Collybias are usually cæspitose, the stems exteriorly cartilaginous, in some species swelling and splitting open in the centre.

In Pleurotus the stem is lateral or absent. The plants are epiphytal, usually springing from the decaying bark of trees and old stumps.

In Clitocybe the plants are characterized by a deeply depressed, often narrow cap, with the gills acutely adnate, or running far down the stem, which is elastic, with a fibrous outer coat covered with minute fibers. Many of the species have a fragrant odor. The Tricholomas are stout and fleshy, somewhat resembling the Russulas, but distinguished from them by the sinuate character of the gills, which show a slight notched or toothed depression just before reaching the stem (represented in Fig. 4, [Plate IV]). Typical species of Armillaria show a well-defined ring and scales upon the stem, the remains of the partial veil, and the plants are usually large, and cæspitose. The Lepiotas are recognized by the soft, thready character of the fleshy portion of the cap, and the fringed scales formed by the breaking of the cuticle. The ease with which the ringed stem is removed from its socket in the cap is another characteristic which distinguishes the plants from those of other genera.

The Amanitas are distinguished by the volva, which sheathes the somewhat bulbous stem at its base and the ring and veil which in the young plant are very distinct features, the whole plant in embryo being enveloped in the volva.

The Amanita group, besides containing some very good edible species, is also credited with containing the most dangerous species of all the mushroom family, and some which are undoubtedly fatal in their effects.[A]