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underground roots, which exceed the reproductive stems in 
both bulk and weight and also completely fill the space they 
occupy almost to die exclusion of the humus soil in which 
they grow. 
These great variations in the comparative size of the root 
and shoot may be reconciled only in the light of the fact that 
the real absorbing organs are the branching strands and 
hyphae, which radiate from the sheathing mycelium, and 
that the size of the root system is one adapted to furnishing a 
suitable habitat to the ectotropic fungus and for the storage 
of surplus material. It is impossible to account for the pres- 
ervation of the large shoot with stomata in Prerospora with 
the data now at hand. 
It is important to call attention to the fact that the vegeta- 
tive period of the association, during which time food and 
therefore energy are being acquired, by no means coin- 
cides with the existence of the aérial shoot. The fungus coat- 
ing the roots may carry on absorption during the entire 
season when the temperature is above the freezing point, and 
the accumulated store is drawn upon by the higher plant for 
the formation of shoots only inlate summer. Growth and the 
formation of buds on the roots may proceed underground co- 
incident with the entire season of absorption of food. 
According to most of the writers who have touched upon 
this point, the roots of adult plants are adventitious and give 
rise to buds, which arise endogenously after the manner of 
the nearly related Pyrolaceae. This fact is confirmed by the 
evidence obtained from the genera under discussion. Main 
or primary roots would therefore be found on seedlings only. 
Members of this family have also lost the power of branching 
of the shoot, except so far as giving off the simple peduncles 
is concerned. The roots show branches of the second and 
third order in all the genera examined. The branches are 
arranged in five orthostichies in Sarcodes according to Oliver, 
in three or four in Aypopitys according to Kamienski, but 
no orthostichous condition may be recognized in Prerospora 
or Afonotropa, although Oliver credits the former with three 
