PLATE 3 



Parasitism of Kbambria canescens on Covii.lea tridentata. 



1, penetration of young haustorium to woody cylinder. The " cushion " of the parasite's haustorium is 

 beginning to form, but tissues are not completely differentiated. 2, transverse section through haustorium. in the 

 cortical region of host, showing occurrence of ducts. 3, detail from a young haustorium showing relation to wood 

 of host. 4, semi-diagrammatic figure of a single duct of CovllUa and a group of pitted cells of a mature haustorium. 

 5, longitudinal section of haustorial cushion showing positions of ducts extending toward tip and curve of tissues 

 in cushion. 6, longitudinal sections of haustorium and host, showing manner of growth of tip of haustorium into 

 woody cylinder of host. The heavy red marginal line indicates the cork formation in parasite. The light black 

 longitudinal line indicates cambium of host. 7, extreme development of haustorium, with great distortion of 

 host root. 



Figures 2, 3 and 4 X 3C2; the other figures X 44. 



