194 DISEASES OF FIELD & GARDEN CROPS. [en. 



two fungi. One may reasonably ask which is the sexually 

 mature condition in Puccinia and dEcidium. If there is 

 any meaning in the words spermogone and spermatia, 

 jflcidium must be the sexually mature condition ; yet the 

 believers in the connection make Puccinia the perfect con- 

 dition, for in describing these fungi the fruit of the ^Ecidium 

 is invariably termed "the dEcidiospore of the Puccinia" 

 This puts Puccinia in the foremost position, and Sachs, in 

 his Handbook, Ed. i., p. 247, prints "Puccinia, graminis" 

 under an illustration which includes Uredo linearis, Pers., 

 Puccinia graminis, Pers., and ^Ecidium Berberidis, Pers. 



When the teleutospores germinate they produce the so- 

 called pro-mycelium spores or larval spores, as illustrated 

 at C and G, Fig. 88. These latter spores, when they in 

 turn change by germination, should give rise to the Uredo 

 spores or pupa state of the Puccinia. If this view is cor- 

 rect, we have every life-stage perfect. 



1. Puccinia, the perfect resting-spore stage. 



2. Pro-mycelium spores, the larva stage. 



3. Uredo, the pupa stage. 



What need is there for another set of spores as found in 

 ^cidium, with their resulting pro-mycelium spores and 

 sporidioles of precisely the same class ? 



At this stage of the inquiry the question presents itself 

 to us If the ^Ecidium and Puccinia are not physiolo- 

 gically related to each other, how is it that Uredo, 

 Puccinia, and ^Ecidium, sometimes grow together on the 

 same host ? Our reply is : It may possibly be a mere 

 state of consortium another of the many familiar instances 

 of two diverse organisms being found in company. The 

 consortism, if such it be, would not be more remarkable 

 than the consortism of Peronospora parasitica, Pers., with 

 Cystopus candidm, Lev., on the cabbage tribe ; of Perono- 

 spora nivea, Ung., and Protomyces macrosporus, Ung., on 

 umbelliferous plants ; of Peronospora infestans, Mont., and 

 Fusisporium Solani, Mart., on potatoes ; of Saprolegnia 

 ferax, Kutz., and Empusa muscce, Cohn ; and many other 



