276 STATE HORTICULTURAL SOCIETY. 



white germ-tubes. These bore their way through the epidermis of the leaf ^ 

 and produce new centers of the disease, i. e., new spots. 



In the latter part of the season the mycelium becomes compact in certain 

 places. Toward winter masses of the mycelium, either ovoid or columnar 

 in form, made up of polygonal cells, the outer Ijrown or black-walled, force 

 their way through the broken epidermis anywhere in the diseased part of 

 the leaf, and may be seen as blackish specks, by the naked eye. These are 

 very numerous on our plants and have been termed by Trelease "sclerotia." 

 If the leaves supporting them are brought, in the winter season, into a 

 warm room, and kept in moist atmosphere, hyphal filaments will develop 

 from the siirface cells of the sclerotia in from twelve to thirty hours, and 

 immediately produce basidia and conidia like the summer form, as Miss 

 Snow has remarked, "there is a striking resemblance between the sclerotia 

 bodies bearing conidia and the later stages of the ordinary conidia growths." 

 Indeed diiring the autumn we have seen all stages between the two ; and 

 although we have termed the hyphal, conidia-bearing filaments of summer^ 

 the early or summer stage, nevertheless this passes so imperceptibly into 

 that seen in Fig. 3, and the latter into the selerotiiini, or winter conidial 

 stage, that the early stage and the sclerotia must be regarded as extreme 

 states of the same phase of life, resulting almost wholly perhaps, from cli- 

 matic conditions. When any fungus forms such sclerotium masses, the 

 purpose is usually protection against cold or dessication; and this state 

 takes the place of a " resting spore," in the case of a parasite, tiding the 

 fungus over to the next growing season of its host. As the sections of the 

 United States where these sclerotia have been noticed and reported as. 

 abundant, namely, in Wisconsin, by Professor Trelease, and in central 

 New York, are in regions of rigorous winters, it would be interesting to 

 know whether they were as abundant in the south. Certainly in this 

 region the sclerotia furnished one of the important and effective modes of 

 carrying the fungus over the winter. 



The perifJu'cia, constituting the fourth state mentioned, begin their 

 development in late autumn, but are not mature in our latitude until March 

 or April. They are found about, or occasionally upon the white center of a 

 spot on an old. apparently dead leaf. They can be seen with the naked 

 eye, as minute black points. Externally the wall is nearly black, and com- 

 posed of large cells. The cavity of the perithecium is lined with delicate, 

 white cells. At the apex is a circular opening in the w^all called the ostio- 

 lum, and from the bottom arise a series of club-shaped, thin-walled sacs 

 called asci. The asci contain eight spores, each of which is oblong and 

 two-celled. These ascospores are capable of a much longer life than the 

 conidia. 



Various opinions have been held concerning the real connection of the 

 conidia and perithecia above described. In 1863, the Tulasne brothers 

 published elaborate figures of both, as well as another, called the stylos- 

 poric stage, asserting them to be forms of a single species, which they 

 called Sfigvudca (now SphaereUa) Fi'dijarUr. Saccardo, however, in 1879,. 

 separated the summer stage from the perithecial, describing the former as 

 Bamiilaria Tiilasnei. Recently Scribner has asserted his belief, based on 

 direct observation, in the correctness of Tulasne's view; but none of the 

 authorities who have written on this subject, have shown us that they 

 were able to propagate one form from the spores of the other, in artifi- 



* One millimeter =^ 1-25 of an inch, nearly. 



