926 
Journal of Agricultural Research 
Vol XXVIII, No. & 
As the spores mature and are discharged, the plugs appear to become rounded. 
(PL 1.) Some of them are dislodged during flight, others fall off as the spore 
comes to rest. One or two plugs may cling to the spore. Herbarium specimens, 
of this rust show these bodies among the spores and they are undoubtedly always 
developed. Any object which could cause such indentations in elastic spore walls 
as are shown in figure 1, C, must certainly serve as a good fulcrum against which 
the spore wall can react as the spore breaks loose from its neighbors. 
Dr. Buffer has called the writer’s attention, in an advance copy of a section 
which he has written for his new book on the fungi, to the work of Zalewski 6 on 
aecidiospore discharge. Zalewski found that in the case of four species of rusts 
the aecidiospores were discharged violently to a distance amounting in some 
instances to 1.5 to 2 cm. He also found that the spores were shot vertically 
to a height of 1.0 to 1.5 cm. This author gave no explanation of the phenome¬ 
non, and offered no suggestion as to the mechanics of the process. 
SUMMARY 
A study was made of the distribution of stomata on leaves of Podophyllum 
infected with the Puccinia podophylli. The host is not stimulated to develop 
additional stomata. 
The germ pores of aecidiospores of this rust are developed as the result of 
localized thickenings of the wall in such a way that little plugs are formed and 
these become separated from the rest of the waff. The plugs, deeply indenting 
the elastic waffs, serve as fulcrums against which the waffs react as the spore is 
set free, so that it is discharged with considerable violence. 
Persistent pore plugs are not developed by the aecidiospores of the orange 
rusts of Rubus. The spores of the long-cycled Gymnoconia are nevertheless 
discharged with some violence. Those of Caeoma nitens, being more waxy, 
tend to cling together and remain in the sorus, where they may germinate. 
• Zalewski, A.—Ueber sporenabschnurung und sporenabfallen bei pilzen. Flora 66: 228-234, 249-271. 
1883. 
