REPRODUCTION 679 



The mycelium in practically all cases, at first consists of a 

 loosely interlacing collection of hyphse which absorbs nutriment 

 from the substance upon or within which it grows. When its 

 component hyphse are abundant, the mycelium resembles a 

 loose tangled mass of soft and delicate, white, cotton-like 

 threads, and in many fungi remains in this form even when it 

 spreads over an area of several square feet. Such mycelia are 

 commonly observed among dead leaves, in manure heaps, on 

 decaying wood, damp walls and rotten organic matter generally. 

 Frequently the hyphse forming the mycelium become closely 

 woven together into long, string-like strands, or flat, spreading 

 sheets, resembling soft felt or even tough leather. 



Among certain species of the higher fungi, the mycelium after 

 vigorous active growth forms compact, firm masses of irregular 

 spherical, cylindrical, or other shapes, varying in size from a 

 pin's head to a doubled fist or larger. These hard mycelia are 

 termed sclerofia, and are generally black or purple on the out- 

 side, and grey or whitish within. The hyphse composing them are 

 compactly united with each other and divided by so many trans- 

 verse septa, that sections through them resemble those through 

 parenchymatous tissue of the higher plants. Fungus tissues of 

 this character are described as pseudo-parenchymatous. Sclerotia 

 contain a store of nutriment and, after their formation, undergo 

 a period of rest of several months : when produced in late 

 summer or autumn they usually remain dormant during the 

 following winter, and in the succeeding spring and summer 

 germinate and give rise to reproductive organs. 



5. Eeproductiou. — As in the rest of the Thallophytes, fungi 

 are reproduced by means of spores, each of which is a single 

 cell set free by the mother-plant and capable of giving rise to 

 a new plant like its parent. 



Great variation exists both in the form and the mode of origin 

 of spores. The commonest spores are spherical or oval, but 

 in certain species they are club-shaped, spindle-shaped, or ever 



