PLATE 46 



A. — Cross section of the stem through one of the hypertrophied lenticels shown in C. 

 In embedding and sectioning most of the loose outer tissues are unavoidably lost. 

 Approximately X 112. 



B. — Large patches of excrescences upon the tap root near the root crown, on Pinus 

 rigida. Approximately X iM- 



C. — Hypertrophied lenticels on root of 5-months-old Pinus ponderosa, grown in a 

 loosely stoppered 2-ounce bottle, in tap water which had not been changed since the 

 germination of the seed. The entire structure of the lenticel, which is too delicate 

 to recover in digging roots from the soil, is here preserved. Approximately X iK- 



