46 



PLANT LIFE. 



occur, and a section of the resulting structure has much the 

 appearance of a section of the tissues of a higher plant (fig. 

 55). These changes are particularly apt to occur among the 

 superficial parts of the more massive structures among the 

 fungi, where they are ne<:essary to impart firmness, rigidity, 

 or durability. For example : in the ergot, a fungus common 

 upon certain grasses, a portion of the mycelium is to survive 

 the winter and grow again the next season. This portion 





f'iG. 54. Fn;. 5- . 



Fig. 54. — rjraachin.i; haustoria of Peroaos/'ora. in ^ /n , the liypha tra\t-rsini:: an 

 intercellular space of the liost ; z, z, two haustoria penetratin,^,' t\vi> cells <.>f 

 the host and branching therein. The other con Leu is of h (.1st -cells nnt shown. 

 Magnified about 400 diam.— After De Bary. 



Fig. 55.— a section through the mycelium of a lichen showin^^ hyplu-e near upper sur- 

 face, a, and lower surlace, />, fused into a false tissue ; only in central region are the 

 filaments recognizable. I'he dark spheres are imprisoned alga;. Magnified 650 diam. 

 —After Bornet. 



replaces the youiig oviilary of the flower (see •^ Z^-iS)' and, 

 as it matures, Ijecomes a dark-colored mass, as firm and re- 

 sistant as the grain itself (fig. 56). 



'i'he inter\vea\'ing and fusion of the hypha^ sometimes pro- 

 duce cord-like or stra|)dike structures of considerable size. 

 The mycelia of the higher fungi freijuently form them, and 



