200 ELEMENTS OF STRUCTURAL BOTANY. 



These rounded bodies are the spores ; the narrowed ends 

 of the cells are called steriymata, and the projecting cells 

 which bear them are specially known as basidia. The 

 spores are formed by the simple narrowing in of the outer 

 ends of the basidia. 



The mycelium is, therefore, the vegetative part of the 

 Mushroom, while the stalked pileus above the surface is 

 the fructification. The mycelium is developed directly 

 from the spore, but so far there have not been dis- 

 covered any indications of the interaction of sperm- 

 cells and germ-cells such as characterize the Bryophytes 

 and Pteridophytes. 



348. You will note the entire absence of green colouring- 

 matter. The Mushrooms produce no chlorophyll, and, 

 consequently, are incapable of assimilation. They are 

 always found growing upon decaying organic matter, as 

 the leaf-soil of forests and meadows, &c. 



349. The Mushrooms are representatives of a l?,rge class 

 of plants called Fungi, all the members of which are 

 destitute of chlorophyll. The cells of which they are 

 made up are generally in rows so as to form long threads 

 which are known as hyphce, and these may be either 

 loosely interwoven, as in ordinary Moulds, or firmly 

 compacted together, as in the Mushroom. 



350. As just mentioned, Mushrooms are saprophytic in 

 their habits ; but there are also Fungi wMch are parasitic, 

 such as Rust and Smut. To the Fungi belong such 

 organisms as the Yeast-plant, and the Bacteria which are 

 found in putrefying matter, and are the cause of, or are 

 associated with, diseases of various kinds. 



