260 



ESSENTIALS OF BOTANY 



Fig. 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 ot coniferous trees. A, 

 fructifications of various ages ; c, c', very young *' buttons " ; st, the stem 

 or stipe ; r, the ring (the remains of a membrane by which the margin of 

 the cap was at first attached to the stalls) ; g, the gills. B , branching myce- 

 lium spread out between the bark and the wood of the root of the host. 



stud/, though the directions which follow might require 

 in some cases to be slightly modified for other genera than 

 Psalliota. 



337. 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 aerial fruiting portion,'^ commonly called 

 the mushroom, and the underground mycelium, or " spawn." Draw 

 the entire portion above ground. 



(J) The stages in the development of the cap and its stalk from 

 the "buttons" (Fig. 185, A). 



(c) The cap, gills, ring, and slalk 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. 



