222 



Prof. Henslow on the Specific Identity 



and an orange powder escaped from them ; few, if any, of the 

 broAvn bhsters burst, the further progress of the fungus having 

 been checked (as 1 suppose) by a change in the weather. After 

 this, many of the scales became filled with a mouldiness, which I 

 believe was occasioned by the discharged spores of the Uredo 

 germinating; but I am not perfectly satisfied of the fact. The 

 orange spores which proceeded from the yellow blisters were 

 those universally recognised by the name of Uredo ruhlgo ; and 

 I have represented the forms which they generally assume, at 

 fig, a. When my attention had become more particularly directed 

 to the inquiry, I soon found several other anomalous forms 

 scattered here and there among the more usual and regular states 

 of these spores. Repeated examinations of the yellow sori, even 

 where there was no trace of brown sori, have confirmed the ob- 

 servations, and I have selected a few of these anomalous forms, 

 and have figured them in the upper division of the plate. In 

 several instances the spores were lengthened, or drawn out into a 

 short pedicel (as at b). The existence of a distinctly formed 

 transparent pedicel was repeatedly recognised (as at e), though 

 this was most generally wanting. It frequently happened, how- 

 ever, that certain spores appeared to be furnished with one or 

 more appendages resembling pedicels, when in fact there was 

 not one : this appearance arises from an optical illusion, produced 

 by slight linear depressions in the surface of the water, when a 

 spore is floating (as at/). These illusory pedicels often appear 

 to proceed from a spot which seems to have been the real point of 

 attachment, and where there is a slight flattening or truncation 

 of the curvilinear surface of the spore. Some of the spores are 

 very irregular and amorphous (as at e) ; and in one instance I 

 observed a sort of double spore (as at d). Lastly, and by no 

 means so unfrequently as to render the observations at all 

 doubtful;, there were several forms which manifested a decided 

 approach to the usual form of the spore of Puccinia graminis 

 (asatg-). 



Turning next to the examination of the broAvn sori; on opening 

 the blisters in which they were enclosed, I found a partial repe- 

 tition of those forms which were most abundant in the yellow 

 S07% viz., spheres and spheroids (as at Ji) ; but there were also 

 a vast number of anomalous forms (as at ?"), as though (from 

 some disturbing cause or other) the usual regularity of their de- 

 velopment had been checked, or interfered with. Many of the 

 spores possessed the true character of Puccinia graminis (as at k), 

 but the great majority might be considered as abortions and mon- 

 strosities, intermediate to the forms of Uredo and Puccinia. 

 Some had one cell (j, m), others two. In some one of the 

 cells only (I), and in others both of them were filled with 



