10 H. MARSHALL WARD. 



remains of the " disease patcli " soon becomes the prey of 

 Bacteria, &c., which follow in the tracts of such parasites as 

 Hemileia. 



The foregoing description will naturally provoke the inquiry, 

 to what group of fungi does Hemileia belong ? Without insist- 

 ing upon an answer to this question, I think it may be worth 

 while to review some of the points in this connection. The 

 general similarity of the " disease-spot " itself to the spots pro- 

 duced by many TJredinece is somewhat striking, and the occur- 

 rence of the orange-red pigment in all the spore-structures, &c., 

 vividly recals the same. The mycelium, ramifying in the lacuna 

 and forming tufted groups here and there externally ; the septa, 

 sometimes separated by long intervals, sometimes more closely 

 arranged ; and again, the centrifugal spread of the fungus, are all 

 points of analogy worth recording. 



It seems impossible to overlook the resemblances of the two 

 spores of Hemileia to the Uredospores and Teleutospores of an 

 ordinary Uredine. In size, colour, ornamentation of the exo- 

 spore, mode of germination, and entry of the germinal tube 

 through the stoma after forming a vesicular swelling over its 

 orifice, we have strong analogies, so far as the papillate spore is 

 concerned. 



The smooth, turnip-shaped spore, in its mode and time of 

 origin, shape, structure and colour, and especially in its germi- 

 nation, so strongly recalls the Uredinea, that I ventured to use 

 the well known name Teleutospore. Indeed, the promycelium, 

 with its four cells and conidia, might almost pass for that of 

 Vromyces for instance. 



Nevertheless, there are some difficulties in referring Hemileia 

 to the ordinary Uredines. The curious spore-bearing head which 

 protrudes through the stoma, and the long-necked haustoria, so 

 numerous on the mycelium, are perhaps the chief. How much 

 weight these difficulties carry may be an open question. In 

 cases where two spore-bearing heads have passed through two 

 closely adjacent stomata, it rarely occurs that the one or two 

 intervening cells have become destroyed ; the two heads here 

 become one common, broad, and irregular receptacle, and very 

 like an ordinary uredinous patch. 



In conclusion, it appears necessary to make a few remarks on 

 the other forms of fungi, believed by Messrs. Abbay and Morris 

 to be phases in the life-history of Hemileia vastatrix. It is 

 impossible to explain all the points raised without numerous 

 drawings, for which there is not room here ; at a future date I 

 hope to illustrate more fully the following brief statements. 



The forms figured by Abbay^ are very common in germina- 

 1 LoQ, cit., PI. 14, figs. 10 to 19, 



