ARTHUR: IMPORTANCE OF THE SPERMOGONIUM 121 
are found arising from the same mycelium, aecidia do not occur in 
the cycle; and if spermogonia and teleutospores are found arising 
from the same mycelium, there are neither uredo nor aecidia in 
the cycle. If we read a diagnosis in which only teleutospores are 
Fic. 2, Diagrams to illustrate the succession of spore-forms, the continuity of the 
mycelium, and the repeating generation, within a cycle of development. 
Curved lines represent mycelium; when the lines branch, two kinds of spores are 
borne by the same mycelium, usually one succeeding the other in point of time ; Il, 
primary teleutospores ; iii, secondary or repeating teleutospores ; I, primary oe ; 
i, Secondary or repeating aecidia ; II, primary uredo ; ii, secondary or repeating uredo ; 
¥, Sporidia ; 0, spermogonia. 
’ ibnibtets eicte of development, the repeating generation being the uredo ; rs 
cycle with the uredo suppressed, the aecidium being the repeating generation ; - cyc 
with the aecidium suppressed, the uredo being the repeating generation - PD, cyce e wit 
both aecidium and uredo suppressed, the teleutospore being the repeating generation. 
mentioned, there is no way of judging whether the rust also pos- 
Sesses aecidia and uredo or not, unless it is stated that the teleuto- 
Spores germinate immediately upon maturity, when usually, ae 
though not invariably, other spore-forms are absent. To mention 
