10 
Colorado Experiment Station 
bearing plants. It is the latter kind, of course, which cause plant 
diseases. Fungi which obtain their food from dead organic matter 
are known as saprophytes. Those which obtain their food from liv- 
ing plants are known as parasites. 
Fungi differ from higher plants also in that they do not have 
leaves, stems or roots. The body of a fungus consists chiefly of a 
fine, branched, thread-like structure, known as a mycelium. This 
branched, thread-like mycelium is usually more or less interwoven 
to form a cottony or woolly mass such as is seen in the common bread 
mold fungus. In some kinds of fungi this mycelium may be so 
crowded together so as to form a solid mass. The common mush- 
rooms are examples of this type of fungus. 
A common mushroom. (Original, bulletin 201, by Longyear.) 
All fungi reproduce by means of very small seed-like bodies 
known as spores. These spores may vary greatly in size and struc- 
ture but they all have the power of germinating and forming a new 
plant. Spores also vary greatly in the way they are produced. The 
form of the spores and the way in which they are produced are im- 
portant as means of distinguishing the different kinds of fungi. 
