256 M. C. COOKE ON BLACK MOULDS. 



in shape, proportionately broad, and divided longitudinally 

 and transversely by numerous septa. These are the spores of some 

 species of Macrosporium, which hitherto have been maintained as a 

 distinct and veritable genus, closely related to Cladosporium, but 

 virtually distinct. Since the appearance of Tulasne's great work, 

 this opinion has been greatly modified, and some authors contend 

 that the spores of Macrosporium are but a more complex form of 

 fruit of the Cladosporium, or that they are a condition of some 

 ascigerous fungus, of which Gladosporium is but another manifesta- 

 tion. On this point I shall not now venture to express a decided 

 opinion, as our design is rather to recognise the various forms than 

 to determine their functions. There are several genera, or supposed 

 genera, with spores of the Macrosporioid type. That is, large, 

 irregular spores, with septa in both directions, dividing the spore 

 into numerous cells. In Macrosporium itself there are threads of a 

 flaccid nature, resembling those of the species of Cladosporium, but 

 not so highly developed, in fact, sometimes scarcely developed at all 

 beyond a short basal stem. The spores appear to be sometimes 

 terminal and sometimes basal, but the spores always appear more 

 prominently than the threads. It is difficult to meet with a speci- 

 men of the ordinary forms of Cladosporium in which spores of 

 Macrosporium are not mixed up. h\ some forms of Macrosporium 

 there is but little or no evidence of the presence of Cladosporium. 

 It is difficult to fix the limits which may fairly be considered as 

 constituting a species in this genus, the spores are so variable in 

 size and form in the same specimen, but, in a few cases the distinc- 

 tion is so marked that there remains very little ground for doubt. 

 Recently the Rev. J. E. Vize has sent me a Macrosporium which he 

 calls M. nubile, with very large and characteristic spores, just such 

 as would please the ordinary mieroscopist and afford an additional 

 object for his cabinet. The species are common enough on dead 

 leaves and stems of herbaceous plants. The leaves of cabbage, 

 both in this country and the United (States, yield a species with very 

 long spores ; it has been called Macrosporium Brassicce here, and 

 M. circinans there, but evidently there is no difference between 

 them. It was long since intimated by my friend the Rev. M. J. 

 Berkeley that there is no essential difference ^between the genus 

 Macrosporium of Fries, and Septosporium of Corda, whilst Mytros- 

 porium and Stemphylium are so closely related that it is very diffi- 

 cult to draw the line between them. In quite another order of 



