148 ILLINOIS ACADEMY OF SCIENCE 



a fern-like colony (Fig. 7), and the type will be classified 

 under that name. 



A second type appeared rarely, and was observed only 

 on the Huntsman apple. It somewhat resembles, under 

 the low power, a cross-section of a honey comb (Fig. 11), 

 and may, therefore, be referred to by that name. On ex- 

 amination with the oil immersion lens, however, almost 

 hyaline hyphal threads, in some instances with hardly 

 distinguishable septa, were observed, branching irreg- 

 ularly over the areas included in the hone}^ comb like 

 cell aggregations. The latter, on their part, are com- 

 posed of sometimes short, many septate hyphae; some- 

 times masses of cells, irregularly grouped and bounded, 

 but with cell walls and septa thicker and darker, and with 

 denser cell contents, than of the hyphae in the more open 

 spaces. The cells of this type measure 2-3 x 2-5/^, being 

 in many instances longer than broad. 



A third thallus type (Fig. 12), which may be named the 

 reticulate type, is characterized by a very large number 

 of long, tenuous branches, gradually radiating from a 

 common center. In general, the cells are 2-4 x 2-5/x, and 

 commonly regular in shape. No peculiarities in budding 

 were noted such as were cited for the first type. Definite 

 anastomosis of cells originating from the hyphal branches 

 which lie more or less parallel, coupled with this regular 

 branching, are characteristic of the type. Branches, com- 

 posed of two and three hyphal rows closely appressed, 

 were commonly noted. 



In the first stages of development of all thallus types, 

 the hyphal threads appear to extend in the same plane. 

 Within a short time, however, there is noted a tendency 

 to form cell aggregations, or a piling up of cells. This 

 results in the formation of large numbers of minute 

 black specks (Fig. 18), generally invisible to the naked 

 eye, and usually not more than lOOiu. in diameter, inter- 

 spersed among the mycelial threads. These are not to 

 be confused with the cell aggregations making up the so- 

 called fly specks (Fig. 18), however, which are much 

 larger, up to 270/^ in diameter, and much less numerous, 

 when present at all. On the other hand, the minute 



