188 DISEASES OF FIELD & GARDEN CROPS. [OH. 



Now we will note liow the phenomena connected with 

 ^Ecidium and Puccinia agree or disagree with the entozoic 

 life-history just given. We commence with the dBtidium. 

 Here we have a sexually mature parasite, with so-called 

 spermogonia and spermatia. The names indicate male 

 organs, with a male fertilising element analogous w T ith 

 pollen. Mr. Plowright, in writing of the spermogonia 

 and spermatia, says : " Their function has not as yet 

 been absolutely demonstrated, but there is little doubt 

 that they play the part of the male element." It is 

 necessary to be exact at this point, for if there is a sexually 

 perfect state of the parasite it must of course be either in 

 the dScidium or the Puccinia ; and if the ^cidium breaks 

 down, the whole hypothesis falls to pieces as far as pub- 

 lished descriptions go. 



We believe the ^Ecidium to be sexually perfect, as 

 indicated by the descriptive terms in general use. The 

 male organs or spermogones are usually, if not invariably 

 produced first, and the sEcidia next ; this phenomenon 

 roughly agrees with the sequence of the stamens and 

 pistils in flowering plants. In Endophyllum and Roestelia 

 the spores resemble the oospores of a Peronospora. We 

 believe that the spores with spermatia attached, as illus- 

 trated in Fig. 86, agree with fertilised ovules. These 

 fertilised ovules, if they agree in habit with the ova of 

 Entozoa, should produce a simple larval form, which should 

 reach the interior of some other plant and there live para- 

 sitically as a larva. The spore of the sEcidium is supposed 

 to so reach the leaves of corn, and to travel to the interior 

 by the stomata. In this position we presume it resembles 

 the non- sexual larva inside the snail. In the entozoic 

 animals in question the larva never reaches any higher 

 stage in its host, the snail : it attains its pupa and perfectly 

 sexual state when it again reaches the mammal. Here 

 the comparison appears to break down ; neither the 

 Uredo or Puccinia can be larval. A larva in fungi can 

 only be some simple conidioid form like the Oidium of 



