Massee : Notes on Puccinia graminis. 



198 



Taot unusual among fungi. Every mycologist knows tliat a great many 

 fungi are developed on a particular matrix only, and this is especially 

 true of the Coniomycetes that are developed on living plants — so much 

 -so, that Dr. Cooke, in describing somQ Indian fungi in Grevillea, v. 8, 

 p. 94, says, It is useless to give names to species of Puccinia or 

 Ti-icJiohasis, of which the host is unknown " ; consequently the 

 strongest point in the argument could be overriden by stating that the 

 Puccinia is parasitic on the Trichoktsis, or <3an only be developed in 

 the pustules made by the latter. To me, the one fact that certain 

 forms of the above-mentioned always succeed each other, proves no 

 more relationship inter se than that which exists betv/een the fungus 

 -and its host. 



How the parasite obtains access to the interior of the plant from 

 which it springs is not known ; it has been suggested that the spores 

 ventered the stomata, but relative size disproves this. When the 

 pseudospores of Puccinia germinate, they emit two threads on which 

 three or four secondary spores are developed on spicules, and these 

 latter in turn give origin to yet smaller sporules, the real value of 

 ■which, up to the present, is a problem unsolved. 



On the leaves of the berberry {Berheris vuhjaris) a minute fungus is 

 not uncommon, called uEcidium berberidis. The spores, which are 

 -bright orange when mature, are at first enclosed in a minute cellular 

 sac, or peridium, which eventually ruptures in a stellate manner, 

 •exposing the spores. Preceding or accompanying these groups of 

 peridia are other smaller ones, known as spermogonia, from the inside 

 of whose walls spring numerous threads, which produce from their froe 

 tips minute bodies, known as spermatia. These ^permogones are 

 .spoken of as secondary organs, but what their functions are has not beeii 

 demonstrated ; by some they are supposed to be .male organs. It is a 

 general belief in agricultural districts that berberry bushes cause corn 

 to mildew, and Prof. De Bary instituted a series of experiments for 

 the purpose of ascertaining whether any such relationship really 

 existed. Germinating spores of Puccijiia graminis were placed on the 

 leaves of berberry plants : the threads, within twenty-four hours, 

 penetrated the tissues of the leaves. In about ten days spermogonia 

 appeared, and soon after the J^cidimn showed itself on the under 

 surface of the leaves — thus seeming to point to the conclusion that the 

 Puccinia and Mcidium are stages of the same plant. The question that 

 naturally suggests itself at this point is, as Mcidium. grows so abund- 

 .antly on berberry, was its presence, in the experiments, due to the 

 infection, oj would it not have appeared at it does on other berbejny 



