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Report on Botany. 



been pronounced by a scientific journal to be a new species 

 of black knot. A microscopic examination of this greenish 

 coating reveals the fact that it is composed of innumerable 

 upright jointed flexuous threads or flocci which bear upon 

 their summit oval or oblong spore-like bodies, at first 

 simple but soon becoming one or more septate. This is 

 the first external development of the fungus and in the 

 systematic classification adopted by botanists it belongs to 

 the genus Cladosporium. This genus, however, we appre- 

 hend is destined to be overthrown, its species being only 

 an early form of development of species of Sphseria. Indeed 

 those celebrated European mycologists, Tulasne and Cooke, 

 already deem the very common Cladosporium herbarum to 

 be only a condition of Sphozria herbarum. And here we 

 have another quite clear case of a similar dimorphism, for 

 I never yet have seen a young black knot excrescence 

 of the cherry tree in spring on which I could not detect 

 the Cladosporium. In a few weeks this Cladosporium 

 growth is succeeded by numerous minute black globular 

 bodies scarcely as large as the head of a small pin. These 

 usually cover the whole surface of the excrescence and are 

 often so closely crowded together that they partially lose 

 their globose form. This stage of the fungus development 

 has evidently been mistaken by some for its complete 

 development. In the work of Harris, on Injurious Insects, 

 we find the following statement in reference to this fungus ; 

 " they come to their growth, discharge their volatile seed, 

 and die in the course of a single summer." And in the 

 Practical Entomologist for March, 1866, we find this state- 

 ment: " Towards the middle of August, the new black- 

 knot, having perfected its seed, gradually dries up and 

 becomes internally of a reddish-brown color. In other 

 words, like so many other annual plants, it dies shortly 

 after it has perfected its seed." Again, in the March 

 number for 1867, Mr. Walsh says : " I showed that black 



