70 



When we consider the close resemblance between the fungi in the 

 two cases under consideration, the case of the orange leaves and the 

 case of the green fruits of the mandarin, and the close resemblance 

 between the results to the tissues attacked, it is difficult to escape the 

 conclusion that the two diseases are identical, so far as we have now 

 proceeded. 



It is, however, necessary to next take notice of the occurrence in the 



diseased tissues of the mandarin skin of a P/ioma-like form. The 



5-8 x 3-6 dark-brown, nearly spherical perithecia of this form 



8-0 x 4-3 ,, were 72-90 /A in diameter, and from within a paren- 



7-2 x 4-3,, chyrnatos shell yielded "colourless spores 3'6-4'3 x 



11 -Ox 4-3" 5-8-1 1 /A. The perithecia were numerous in some 



, " cases, and it was impossible to avoid the conclusion 



Range, that they had much to do with the disease. Ad- 



Avera Vs^x^cT jacent are some measurements of the spores of the 

 Phoma. 



Both forms of the spores found in connection with this mandarin 

 disease were submitted to culture in a sealed infusion of mandarin 

 peel. 



In a few minutes the Alternaria spores started to throw out four 

 to five colourless septate threads, which in twenty-four hours became 

 four to forty times as long as the spores themselves, beginning to 

 branch somewhat after they had reached a length several times as 

 great as that of the spores. 



The spores of the Phoma, after twenty-four hours, began to 

 germinate in a partial manner. In no instance was the new mycelium 

 longer than the spore itself. In some cases buds were formed at one 

 or both ends of these spores. 



I have already remarked on the similarity of these cases. The 

 resemblance is so great that I do not consider them specifically distinct; 

 they are one and the same thing in my opinion, though of course this 

 opinion is based on form, not on complete culture experiments. 



MELANOSE (?) ON ORANGES. 



THE following notes may be worthy of attention in connection with 

 the cause of the disease I formerly described in this journal under 

 the title " Melanose (?) " : 



1. The disease starts at the stomata. This fact points in the 

 direction of the cause being a vegetable parasite ; we know of a 

 number of fungi that effect an entrance by this door, and these fungi 

 belong to widely different groups. On the other hand, is there a 

 single animal parasite that enters by way of the stomata ? Is there 

 one well known to choose the stomata as the scene of its operations of 

 any kind ? Any small insect, to take a supposable example, that 

 wished to utilise its beak for sucking the juices of the plant, would 

 hardly find it convenient to utilise the stomata, for it is precisely here 

 that the tissues sought as food are least accessible, on account of 

 the subjacent air-space and loose parenchyma. 



