352 



THE FUNGI WHICH CAUSE PLANT DISEASE 



C. comptoniae Arth. 



I (=Periderinium pyriforme) on Pinus trunks. Ill on Comp- 

 tonia. 



The Peridermium is perennial in the trunks of the pine where 

 it does considerable injur\'. Clinton sowed aeciospores from pine 



Fig. 256. — Cronartium comptoru;£ (PehdermiumJ on 

 Pinus. After Clinton. 



on Comptonia and in about twelve daj^s the uredinia began 

 to appear.^''' 



C. quercus (Brond.) Schr. 



Hetercecious I (= Peridermium cerebrum) on pine. Ill on 

 oak. 



Successful inoculations were first reported by Shear, -*^ later by 

 Arthur and Hedgcock.-*" Globoid swellings 5-25 cm. across are 

 formed on pine trees. 



C. asclepiadeum fTTil.) Fries. 



Hetercecious I (=Peridermium comui) on Pinus silves- 

 tris. 



II and III on CjTiachum, Pseonia, Gentiana and several other 

 hosts. European. 



The mycelium is perennial in pine twigs and gradually kills 

 them. 



