234 DISEASE OF THE VINE. 



transformation of one organ into the others became perfectly 

 clear ; sometimes also I met with fructifications contracted in the 

 middle as if they were formed of two joined together. All these 

 details are faithfully introduced in the preparation No. 2, which 

 shows at a glance on a highly magnified scale the whole develop- 

 ment of the cryptogam.* 



On carefully examining with transmitted light, and with a 

 magnifier of at least 600 diameters, the sporangia of our 

 cryptogam, we find them to consist of a coloured cellular mem- 

 brane, with the polygonal faces somewhat convex, and which 

 includes some hundreds of spores, which, at their maturity, issue 

 in jets by the mere action of water (I counted as many as 289 in 

 one heap). The form of these spores, which ai'e tolerably trans- 

 parent, much resembles that of the sporidia of some lichens. 

 They are reuiform and ovate-oblong, and under a very powerful 

 object-glass, two little cavities may be observed at their extremities, 

 containing a most minute globule of some denser matter. The 

 preparation No. 3 represents a sporangium with its contents 

 magnified to 1800 times the diameter. f 



Probably the spores which I have mentioned are the repro- 

 ductive corpuscules, which Professor Pietro Savi saw vegetate 

 under the microscope, believing them to have issued by a regular 

 longitudinal dehiscence from the utricles of the moniliform 

 filaments which had been supposed to be the sporangia. But 

 this opinion, although maintained by other eminent botanists, is 

 at variance with the facts shown by my own observations. The 

 preparation No. 4 includes five of the above-named utricles, magni- 



* The publication of the present paper as it was communicated to the 

 Academy of Georgofili required the addition of some figures for the eluci- 

 dation of the descriptions, to supply the place of the preparations in relief, 

 which could not be placed before the eyes of the reader. The distinguished 

 botanist, Adolfo Targioni Tozzetti, having offered to furnish some drawings 

 corresponding to the principal figures in wax, I have here to express my 

 obligations to him, which I feel the more from the circumstance that as he 

 has drawn all the details faithfully from what he has seen himself under 

 the microscope, his figures give an authentic testimony in confirmation of 

 the facts I have described. 



Fig. 1 represents a small portion of the surface of a Grape on which the 

 cryptogam has spread itself, magnified to 300 diameters. From the mycelium 

 arise moniliform filaments m, and the sporangia s. Two of the latter have 

 an utricle directly attached to their upper extremity. 



f In Fig. 2 the sporangium is represented magnified to 600 diameters, 

 and by its side are the spores it has emitted, which, taken separately, are 

 as transparent as white glass ; seen in a mass they have a very slight yellow 

 tint. In Fig. 3 are three spores magnified to 1800 diameters, in order to 

 show the nuclei or globules at their extremities. 



