32 Thikty-foukth Annual Report of the 



all affected pumpkins or squashes at once from the vicinity of the 

 unaffected ones; second, cut out and destroy all the affected spots as 

 soon as detected; third, keep in as low a temperature as possible with- 

 out freezing. 



Mycologists have instituted two genera of molds that are very closely 

 related. In one, which they call Mucor, the globose head that contains 

 the spores bursts irregularly when mature. In the other, which they 

 call Ascophora.h collapses or falls down over the top of the stem, and 

 then presents an appearance similar to that of a miniature spread 

 parasol, or of a saucer inverted and supported on a slender stick. In 

 the black squash mold both these characters exist, for sometimes the 

 head collapses and sometimes it bursts irregularly. If young specimens, 

 while yet white, are placed in a warm dry place their further develop- 

 ment is sometimes checked and then especially the heads collapse as in 

 Ascopliora. Thus it will be seen that satisfactory generic characters 

 and generic limits have not yet in all cases been ascertained. 



Fusicladium dendriticum, Wallr. Apple peel Fungus. (Plate 4, 

 tigs. 1-3.) Probably every one has observed the small, round, black- 

 ish spots common on apples, but perhaps not every one is aware of 

 the cause of them. These spots are not always uniform in color, but 

 are varied by lighter and darker patches or circles. They often have 

 a cracked or scaly appearance. Sometimes they are bare and nearly 

 smooth and then they have a dull reddish tint, but generally they have 

 a blackish or blackish-brown color, more or less tinged with gray or 

 dark-green. They are generally from one-eighth to one-fourth of an 

 inch in diameter, but sometimes they are even larger. There may be 

 but one or two on an apple, but usually they are more numerous, 

 sometimes even so numerous and close that two or more rim together. 

 When examined microscopically it is found that they are produced by 

 a fungus, whose dense stratum of threads and spores gives a somewhat 

 velvety appearance to the surface. The fungus develops beneath the 

 epidermis or thin outer skin of the apple, which at length ruptures, 

 breaking up in small flakes or fragments which remain attached for 

 some time, giving a grayish tint to the spot. The margin is generally 

 well defined but minutely irregular. It may be either darker-colored 

 or paler than the center. The threads and spores are colored and 

 very variable, scarcely any two being exactly alike. Some of the 

 threads are long and prostrate, others short and upright. The spores 

 vary from subglobose to elliptical, fusiform, oblong or narrowly pyri- 

 form. They are generally simple, but sometimes when old they are 

 divided by a single transverse septum or partition. Occasionally they 

 contain one or more nuclei or shfning oil globules. The fungus does 

 not affect the apple deeply, its injury being limited to the surface. It 

 is all taken off with the peel and does not detract materially from the 

 weight or quality of the flesh. Still it injures the appearance of the 

 fruit, and possibly in this way affects the sale of it. It is said that it 

 sometimes opens the way for the attack of other fungi by cracking the 

 epidermis of the apple, but this is not a common result. All varieties 

 of apples are not equally subject to its attacks. Common fruit and 

 especially that growing on trees in the borders of woods seems more 

 liable to its attacks than fruit on thrifty, well -cultivated trees. This 



