THE FUNGUS BODY. 



31 



from a single cell, and is comparable to the thread-like body 

 of the filamentous algae. 



There is, naturally, a great variety in the hyphje of differ- 

 ent species of fungi. Some are relatively large ; others very 

 small ; some of even diameter and caliber, others irregular 

 and with unequally thickened walls ; some very thin-walled, 

 others very thick-walled. Between these extremes is to be 

 found a complete gradation. 



They grow in length at the apex only. In many kinds 

 partitions are formed at more or less regular intervals, as the 

 growth in length proceeds, while in others no partition-walls 

 are formed. Even when transverse partitions form, they do 

 not separate the filaments into cells, but each chamber, or 

 sometimes the whole filament, represents several or many 

 cells. (Compare ^26.) 



42. Branching. — As the hyphs elongate, branching may 

 occur. If a branch is to be formed, a limited area of the 

 cell-wall begins to grow more rapidly than the rest. This 

 allows a slight bulging of the growing region ; the swelling 

 increases and soon takes the form of 

 a branch, like the main axis. It may 

 remain short or continue to grow 

 indefinitely in length. Commonly a 

 cross-wall is formed at the base of the 

 branch. If such a branch arises first 

 as a minute pimple, so that it remains 

 connected with the parent axis by a 

 small neck, and has only limited 

 growth in length, it is called a bud ^'^-^^^ 

 and the process is known as budding 

 (fig. 29). Such branches are usually 

 easily broken off, thus readily produc- ^^^^^^ "o diam, 

 ing independent plants. (See further 

 under Reproduction, ^261.) In some species of fungi, 



Beer-yeast (Jflcc^rtjo- 

 jnyces Cfrevisiee). a, a full- 



;rown plant with a branch 

 (bud) partially developed. ^, 

 c. colonies formed by budding, 

 the individuals still attached. 

 After 



