336 



METHODS IN PLANT HISTOLOGY 



^m^-^9^w^mm 



Fig. 116. — Piniis strobus: photomicrograph of longitudinal radial section of mature wood of 

 stem, showing bordered pits and bars of Sanio. Safranin and crystal violet. Eastman Commercial 

 Ortho film, Wratten B filter (green) ; Spencer 4-mm. objective, N.A. 0.65; arc light; exposure, j sec- 

 ond. Negative by Dr. P. J. Sedgwick. X 166. 



