528 IOWA ACADEMY OF SCIENCE 



PICE A IWBENS Sarg. Red Spruce. 



Leaves 4-angled, y 2 to % inch long. 



Resin ducts 2, small, lateral, touching strengthening cells on 

 ventral side below the angles, ducts lined by two layers of 

 lignified cells. 



Vascular bundle — Xylem very slightly divided, a group of thick 

 walled lignified strengthening cells below phloem. Xo ligni- 

 fication of pith, cells of bundle sheath lignified where joined. 



Hypodermal cells around entire periphery, thick walled except 

 along stomata bands, one layer thick and lignified. 



Parenchyma walls slightly corrugated. 



Stomata 4 rows on each upper side. 

 2 rows on each lower side. 



Material obtained from C. S. Sargent, 

 Jamaica Plains, Massachusetts. 



Plate XLII. 

 Figure 1. — Section of leaf of Picea rubcns. 



Figure 2. — Section through epidermis and stomata of leaf of 

 P. rubcns. 



Figure 3. — Section through resin duct of leaf of P. rubens. 



Figure 4. — Section through vascular cylinder of leaf of P. 

 rubens. 



