242 DISEASE OF THE VINE. 



you in a state of fructification, whilst hitherto it has constantly 

 appeared to me, as well as to all others who have contemporaneously 

 or successively examined it, in a sterile state ; and I am the more 

 sincerely thankful to you, inasmuch as having availed myself of 

 the excellent microscopes you possess, I have been enabled to obtain 

 so clear a view of the form of the spores, and of their connection 

 with the mycelium, and with the summits of those utricles which 

 I had hitherto considered as perfect sporangia, that I no longer 

 entertain any doubts of their existence, and am fully persuaded 

 of the correctness of your opinion. 



On studying mycological works with a view to ascertain where 

 to place this little fungus, and, judging from the characters 

 which you have explained in your Memoir to the Academy 

 of Georgofili, which correspond exactly with those which I 

 had drawn up with your assistance, I must say that the genus 

 to which it belongs appears to me to be a new one, for I do 

 not find in Corda's Icones fungorum hucusque cognitorum any 

 figure or description which resembles it. The only form with 

 which at first sight it appears to have some analogy would be that 

 of the genus Sporidesmium, but the want of mycelium, the 

 dimensions of the parts, and the form of the sporangia so 

 different from those of our species, separate them from each 

 other. I am, however, obliged to give up the determining it 

 with any accuracy ; the want of mycological works and of sufficient 

 experience in this vast and difficult branch of botanical learning, 

 prevent my even ascertaining with any certainty whether it is or 

 not a new generic or specific form. 



With regard to the doubts you express as to the possibility of 

 my having mistaken a longitudinal fold in the utricles for an 

 apertui'e, I candidly confess that if I am disposed to acquiesce in your 

 supposition it is more from indirect conclusions tban from direct 

 evidence ; for I must say, that, even with the vast means you have 

 afforded for microscopical observations, I have always seen so 

 great a semblance of an aperture that I could not convince myself 

 of its non-existence, and were I to trust to my eyesight alone, I 

 should see no reason to change my opinion. It is nevertheless 

 true, that I have never had under my eye either the actual 

 operation of dehiscing nor that of the emission of the sporidial 

 matter supposed to be contained in the utricles ; that there is a 

 considerable difference in form between the spherules of this 

 sporidial matter and that of the seminules which accompany the 

 germination ; and that these facts combined with your reiterated 



