FUNGI. 229 



large one and contains many common moulds (Chap. X. 

 p. 2 I o), yeast (Chap. X. p. 2 i 2), and most of the lichen-fungi 

 (Chap. XII.). The mycelium of most of these penetrates 

 rotten wood or decaying matter and the fruit is more or 

 less ^?//-shaped, and quite like that of the lichens with 

 very often the same red or yellow colours. The bright 

 red Peziza coccinea with cups i to 3 inches in diameter 

 is exceedingly beautiful, especially when the old logs on 

 which it grows are covered by bright green mosses. 

 Most of the Ascomycetes are how^ever very small, often 

 only an -g- of an inch in diameter, and must be carefully 

 searched for. The cups are often supported on little 

 stalks ; and sometimes, as in the Morels {Morchella), the 

 asci and barren cells cover an irregular wrinkled surface 

 spread like a cap over the top of a stout support. In 

 one group, the mycelium develops inside the bodies of 

 grubs or caterpillars, and the supporting stalk ends in 

 an orange club-shaped mass which contains many little 

 cavities, each containing asci and barren cells {Torrubia 

 militaris). 



In the sub-division Pyrenomycetes, the mycelium is 

 similar, but the ascus part is compound and there are 

 many little pits in which the asci are enclosed. Of 

 these Nectria ci?inabarina is exceedingly common. This 

 is the fungus which forms hundreds of brilliant red 

 spots which break through the bark of dead twigs. 

 Another species, fortunately not so common, N. 

 ditissima, produces the " canker " of Beech, Apple, Ash, 

 and other trees. The spores fall on a wounded part of 

 the trunk and the fungus threads produced from them 

 at once attack the living tissues on each side. This 

 part of the tree ceases to develop and the neighbouring 

 cork-forming and bark cells at once begin to develop 

 cork and multiply rapidly ; the result is a ragged black 



