132 AMERICAN JOURNAL OF BOTANY [Vol. 9, 
Table 18. Measurements in Cross Section of Phloem Root Cells of Cuttings of Trees of 
Salix nigra, Group C 
Ave. Measure, 
Number of Tree Diameter ot Tree 5 Cells 
(Inches) ^ (Microns) 
35 10+ 8.46x7.07 
44 10 7.30x8.30 
48 10 8.76x7.63 
326 13 6.97x9.03 
605 8 6.30 X 8.30 
624 10+ 6.64x7.30 
628 8 7.49x6.97 
630 10 5.81 X 7.64 
631 8-10 8.01 X 7.47 
632 10+ 5.98x6.79 
634 10 7.97x6.64 
643 10 6.64x5.31 
Average 7-i9 x 7-37 
Table 19. Measurements in Cross Section of Xylem Root Cells of Cuttings of Trees of 
Salix nigra, Group A 
Ave. Measure, 
Number of Tree Diameter of Tree S Cells 
(Inches) (Microns) 
76 \ 11.62 x 14.60 
302 9-13 X 8.57 
306 8.30 x 6.03 
308 I 8.30 X 7.62 
318 1^ 8.30x10.95 
321 10.62 X 8.30 
340 —I 16.26 X 18.26 
343 -I 8.29 X 9.96 
357 —I 11.62 X 11.62 
364 -I 15.27x15.60 
401 2 8.30 X 9.95 
606 2 9.29 X 11.95 
608 2 14.27x15.27 
636 9.96x10.95 
637 2 14.27x13.94 
707 2 14.27x13.28 
710 I 11.28 X 8.07 
713 I 13.28x10.95 
714 ih 11.62 X 13.28 
715 2 9.95 X 9.44 
716 I 9.15x11.62 
717 2 8.63 X 9.62 
719 i| 10.62 X 8.69 
720 l|-2 7.30 X 6.64 
724 2 12.08 X 12.41 
733 I 13.28x15.93 
734 I 13.61 X 13.94 
735 2 9.70 X 9.62 
737 I 11.25x11. 12 
Average 11.03 x 11. 31 
