104 The Evolution of the Higher Uredinece. 
The views here put forward concerning the evolution of the 
Uredinese are expressed diagrammatically in the accompanying 
figure (Fig. 2). 
Fig. 2. Diagram representing the Evolution of the higher Uredineas. 
EXPLANATION. The prefixes and suffix can be applied to any genus. 
Taking Puccinia as an example: Pucciniopsis represents the stage when the 
primitive jecidio-teleutospore is divided into two spore-forms, an aecidiospore 
germinating conidially and a teleutospore germinating basidially ; Auteupuc- 
cinia is an improvement upon this, because the intercalation of numerous 
generations of uredospores improves the facilities for dispersal; Hetereupuc- 
cinia is again an improvement, since in this case the fungus can form its spores 
upon hosts that completely disappear during the unfavourable period, if the 
alternate host survives ; Brachypuccinia and Micropuccinia show adaptations 
in another way by shortening the development and quickening the formation 
of teleutospores, thus enabling the species to exist in subarctic or alpine 
regions—many Micropuccinise still retain the spermogones, others have 
completely lost them ; Hemipucciniae are a mixed group, as explained in the text. 
SUMMARY. 
The conclusion at which I wish to arrive is this :—The primitive 
ancestors of the Pucciniaceae possessed only one spore-form 
(aecidio-teleutospore) and were restricted to one host or to a series 
of closely allied hosts. From these arose cases like those of 
P. Tmgopogi and Uromyces Cunninghamianus, where the aecidio¬ 
spore germinated conidially and produced on its mycelium a 
