INTRODUCTION. 
Fungi, the larger fungi, are divided into two 
classes, 1st, the Basidiomycetes, which have the 
spores borne free on a basidia; 2nd, the Ascomy- 
cetes, which have the spores borne in a sack called 
an ascus. In this pamphlet we have to deal only 
with part of the first class. 
The Basidiomycetes can in turn be divided 
into two very natural classes, 1st, the Hymenomy- 
cetes, those that have the spores exposed and free 
from the beginning, or at least from a, very early 
state ; 2nd, the Gastromycetes, those that develop 
the spores in cavities or chambers within the tissue of 
the ptant. We are aware that these divisions are 
not in keeping with the very latest authorities which 
primarily divide the Basidiomycetes into sections 
based respectively on septate or nonseptate basidia, but we believe that 
these latter divisions while possibly theoretically correct, tend only to 
confuse matters excepting to the advanced and expert student. 
It should not be inferred from the above that in order to recog¬ 
nize the Gastromycetes it is necessary to study the nature of the ba¬ 
sidia, or make other minute anatomical examination. As a matter of 
fact, the merest tyro soon learns to recognize on sight the various 
phalloids, bird-nest fungi, and various kinds of “puff-balls” consti¬ 
tuting the Gastromycetes and they were well classified before their 
anatomical structures were known. 
Terms used in the description of the Gastromycetes. 
PERIDIUM. 
The shell or hull, enclosing the spore mass of a gastromyces 
is called the peridium. It varies in the different genera, the simplest 
type is a simple, uniform layer such 
as surrounds the spore mass in the 
accompanying cut of Scleroderma. 
(Fig. 2.) Usually however, the peri¬ 
dium consists of two distinct layers, 
called the outer peridium or exoperi- 
dium and the inner peridium or endo- 
peridium. In Geaster, the outer 
peridium is thick and when the plant 
(*) ripens it splits in a stellate manner 
separating from the inner peridium 
and becoming more or less reflexed. 
(*) In speaking of the “plants” it will be observed that we do not use precise language for 
what we call the “plants” are really the fruit bodies, compound sporophores, of the fungi, corre¬ 
sponding to the fruit of flowering plants, but it seems more natural in a work intended largely 
for general distribution to call a “puff-ball” or a “toad-stool” a plant than a fruit body. The 
vegetative portions of fungi, corresponding to the stem of flowering “plants” are thread-like 
growths called the mycelium, that permeate the soil or rotten wood, and which in reality bear 
the fruit bodies, or sporophores, that we have chosen here to call plants. 
2 
a—A basidium, bearing spores, 
b—An ascus, containing spores. 
