260 ESSENTIALS OF BOTANY 
Fic. 185. Armillaria mellea (often known as Agaricus melleus). 
This is a basidia fungus which can live either as a parasite or a saprophyte. 
As a parasite it is very destructive to the roots of coniferous trees. A, 
fructifications of various ages; c, cl, very young ‘“‘ buttons’’; st, the stem 
or stipe; 7, the ring (the remains of a membrane by which the margin of 
‘the cap was at first attached to the stalk) ; g, the gills. B, branching myce- 
lium spread out between the bark and the wood of the root of the host. 
study, though the directions which follow might require 
in some cases to be slightly modified for other genera-than 
Pesalliota. 
- 83%. Gross Structure. — Secure a group of perfect specimens which 
have been dug up with some of the mycelium attached. Note: 
(a) The division into an aérial fruiting portion,! commonly called 
the mushroom, and the underground mycelium, or “spawn.” Draw 
the entire portion above ground. 
(b) The stages in the development of the cap and its stalk from 
the “buttons” (Fig. 185, A). 
(c) The cap, gills, ring, and stalk of a fully developed mushroom. 
Observe the mode of origin of the ring. 
1 The word ‘‘ fruiting ” is often used with reference to spore-plants to apply 
to the spore-bearing portions or the spore-producing condition. 
