534 IOWA ACADEMY OF SCIENCE 



PICEA PARRYANA Sarg. Blue Spruce. 



Leaves 4-angled, 1 inch to iy 8 inches long. 



Eesin ducts 2, large, at lateral angles of leaves or slightly below 

 the angles, 2 rows of cells lining ducts, inner layer of lignified, 

 irregular flat cells. 



Vascular bundle — Xylem bundles separated by two rows of 

 long narrow lignified cells, large irregular cells above xylem 

 lignified, also the large irregular cells below phloem lignified, 

 cells of bundle sheath lignified where joined. 



Hypodermal cells lignified, in 1 row around entire periphery, 

 thickening into 2 rows at upper and lower angles of leaf. 



Parenchyma walls smooth. 



Stomata in 4 to 7 rows on each side of leaf. 



Material from Campus of Iowa State College. 



Plate XLV. 



Figure 1. — Section of leaf of Picca parryana (pungens). 



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

 P. parryana. 



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



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

 parryana. 



