Ot :\[TLnKW OF THE 



iu lichens {Mem. p. 108), but differing from those ohserved by 

 Amici, and from all that 1 have myself examined, in resembling 

 exactly the true sporangia and in being furnished with similar 

 appendages. In no single instance has this been the case in the 

 species I have had the opportunity of observing, and though in 

 some cases the bodies were globose, this was not by any means 

 their normal form, far the greater part being pointed above. 

 Like M. Tulasne, neither myself nor Mr. Broome have ever seen 

 the pycnidia surmounted by a necklace of utricles, but in every 

 case rising immediately from tlie mycelium very much as repre- 

 sented in the figure in the Hedwir/ia, quoted above, but frequently 

 also from one of the swollen cells of the decumbent mycelium; 

 there is, however, no reason to doubt that such is the case, for 

 the practised eye of Amici could scarcely be deceived; and Dr. 

 Plomley's figures, made two years before those of Amici, and 

 verified by the numerous observations of 1853, are altogether 

 confirmatory of the fact. In one or two instances in Cesati's 

 specimens (Fig. 4, b), Mr. Broome found a few delicate threads 

 at the base of one of the pycnidia attached to its walls, but by no 

 means emulating those of the sporangia. The bodies contained 

 in the pycnidia do not differ much in size iu the different species. 

 In the grape mildew they are (at least in Amici's specimensj''^ 

 '0004 of an inch long, iu that of the gourd, Plantago major, the 

 hop, and Convolvulus arvensis, "0003, and in Trifolium pratense 

 they vary from "OOO^ to -0004. 



No one has at present seen these bodies germinate, unless 

 indeed, as Amici suspects, they are what 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 sporangia." 

 Now it does not seem very probable that Savi could have made 

 such a mistake, as the pycnidia are differently coloured, the colour 

 indeed often extending down the peduncle; and the observations 

 which I have now to record resting entirely upon the repeated 

 and long-continued examination of Dr. Plomley, confirm what is 

 advanced by the Italian Professor. Both in the hop and vine 

 mildew, he found that the joints of the moniliform threads, though 

 not transformed into pycnidia, contained a number of distinct 

 bodies, and not merely a granular endochrome. In both cases their 

 number appeared to be normally about 300, but in the hop mildew 



* Iu Cesati's specimen the contents of the pycnidia did not exceed '0003 in. 



