18 Halsted : MvcoLOGicAL Notes 



) 



normal plants have the foliage quite generally spotted with it. 



In a bed of fruiting radishes the writer had also noticed that 

 certain plants will have the inflorescence malformed by the Perojto- 

 spora parasitica (Pcrs.), while others close at hand were victims of 

 the Cystopns candidits (Pers.) ; but it is rare that a flower or seed 

 vessel bears both of these common fungi. ■ To a limited extent it 

 would seem that the radish infested with the white mould is immune 

 from the mildew, which is generally considered as its general asso- 

 ciate and because of the supposition that it feeds upon the Cysto- 

 pns it has received parasitica as the specific portion of its name. 



If the observations were extensive enough the statement pos- 

 sibly might be made that a wheat, rye or out plant afflicted as it 

 is, if at all, with smut from a seedling on, would be at least par- 

 tually immune from the rust. The smut gains entrance to the seed- 

 ling and possibly renders the host unsuited to the entertainment 

 of other funn-ous rrucsts. 



fc.^"-^ fc> 



Effect of leaf Fungi upon autnnin Coloration of Foliage. 

 Very striking illustration of the eflect of leaf fungi upon the 

 autumnal coloring of foliage was met with this year in the case of a 

 tree of the hard or sugar maple {Acer saccharnm Marsh). The 

 leaves were mottled green and pale lemon yellow, particularly those 

 upon the lower and inner branches, while the upper foliage of the 

 tree and that exposed more fully to the sun was nearly uniformly 

 yellow. It would seem from an inspection of the tree that the 

 mottling was associated with shade and perhaps the coolness and 

 longer periods of moisture that attend the protection of the foliage 

 from the direct sunshine. 



- • 



The spots upon the otherwise yellow leaves were of all sizes 

 but averaged a half inch or so in diameter and were of a green 

 color, irregular in outline and disposed without order, some leaves 

 having but one green blotch while' others had nearly the whole 

 area occupied by them. Fig. 2 shows a leaf with the blotches. 

 The color values of green and yellow are so nearly the same as to 

 make it difficult to get a sharp photograph of the spots. 



A 



variably 



the blotches, it being' the common maple mildew {Uncinula circi- 



