36 JOURNAL OF THE 



in most cases in the death of the affected part of the leaf, 

 producing a marked appearance in contrast with the unaf- 

 fected portions, usually termed a "spot." One or more of 

 these spots occur on a leaf, their form varying from cir- 

 cular to angular, or irregular to very indefinite. In many 

 cases the resulting color changes, due to a partial disorgan- 

 ization of the chlorophyl, to a development of erythrophyl 

 or other coloring substances, gives variety to the circumfer- 

 ence of the diseased areas or to surfaces of the leaf opposite 

 that on which the fungus is located. In a number of cases 

 there are no well defined spots, but the fungus is diffused 

 over small or large areas of leaf surface, giving to those 

 areas the characteristic color peculiar to the species, being 

 roseate in C. effusai^. &C.)K11., ferrugineous in C. lateritia 

 Ell. and Hal., etc. In the case of C. catcnospora Atkin- 

 son the fungus is diffused over large areas of leaf surface 

 and quite injurious, producing a decided "leaf curl." 



The vegetive portion of the fungus consists for the most 

 part ot colorless mycelium made up of filamentous, septate 

 bodies irregularly interlaced among themselves and the 

 cells on the interior of the diseased portions of the host. 

 These contain protoplasm, they grow by longitudinal 

 extension and division of their end cells and by branching. 

 Further formation of cells probably takes place by the 

 division of older cells. Their nourishment is obtained by 

 absorbing materials from the cells of their host. 



Following the vegetive condition is the conidial stage. 

 Provision is made for the production of conidia and their 

 easy dissemination by means of specialized fungus threads, 

 or fruiting hyphae, properly conidiophores^ usually termed 

 briefly by systematists Jiyphce, These arise in more or less 

 divergent or compact fascicles, which stand perpendicularly 

 to the leaf surface and project beyond it. In a few cases 

 some of the vegetive threads ramify on the surface of the 

 leaf and produce conidiophores in a diffuse manner. The 



