250 M. C. COOKE ON BLACK MOULDS. 



globose, or pear-shaped spores, without a septum. Either the 

 forms with septate spores which have been included within the 

 genus must be transferred to 1 1 clminthosporium, or the limits of the 

 genus must be enlarged, and all species of Helminthos porium with 

 obovate or pyriform spores must be transferred to it ; such, for 

 instance, as Helminthosporium obovatum, and, perhaps, H. turbinatum. 

 Here is one of the difficulties with which the student has to contend. 

 No one has concentrated himself to the work of pruning and 

 arranging the whole group in the form of a monograph ; hence the 

 different genera are but too often isolated, and do not in their 

 characters bear a proper relationship to each other. They are a 

 family without cohesion. Sometimes we encounter two or three 

 genera which do not differ materially, if at all, from each other ; 

 and in some other genera we find one author holding broad views, 

 and another very narrow views, as to its limits. This undoubtedly 

 is a source of difficulty to the student, whilst at the same time it 

 serves to indicate a field of legitimate work, and may serve ' as an 

 incentive to master the difficulties of the situation. 



Some of the species of Helminthosporium differ very little, if at 

 all, from the strict interpretation of Monotospora, until we reach 

 the spore. Here there is, and should still continue to be, a clearly 

 denned distinction. One of the most interesting and beautiful 

 species of Helminthosporium is one figured by Corda in his " Pracht- 

 flora " as Helminthosporium Stemphylioides. When in Scotland to 

 attend the Fungus show at Perth, I remained a few hours at 

 Edinburgh, and then, whilst passing through the Botanic Gardens, 

 picked up two little pieces of stick which I saw were inhabited by a 

 black mould. On one of these was the present species, not before 

 recorded in Britain ; on the other the somewhat rare H. Rousselia - 

 num, with the curious Sporochis/na mirabile. Soon after reaching 

 home Mr. Phillips, of Shrewsbury, wrote informing me that he also 

 had found H. Stemphylioides. This species is so characteristic that 

 no other is likely to be confounded with it. The threads are 

 slender, short, and collected in bundles ; the spores are very large, 

 egg-shaped, uncoloured at each end, but with a broad band of 

 brown about the centre. In fact, it is not a good type of Helmin- 

 thosporium, being much more like a species of J\/yst?-osporiu?n, and 

 when the monograph of the Dematiei is written will probably be 

 transferred to that genus. 



It would be impossible for me to refer in detail to the different 



