113 



/VAfVv^V\V 



Y\ 



PIG. I.— BOTRTTIS ISFESTAKS. 



(1) Head, or spores of tlie fungus. (-2) Mychiim, cr spawn. (3) Cuticle of leaf 

 of potatoe. (4) Cellular tissue. 



The figure shows the manner in which the mycehum or sj.awn 



of the funiius ramifies through the cellular tissue of the leaf. 



'^■''^« 4^ 



(1) fEEDO TJUBioo {Common liuaf.) 



200. The minute vegetable organisms called /?/«^«, are cellular 

 -lants having neither leaves, stems nor roots. Their organs of 

 T^ntrition consist of a series of filaments called the Mycelium 

 (fig. 1, 2), {mykes, a fungus) or spaw-n, vvhich spread like a net- 



