564 IOWA ACADEMY OF SCIENCE 



ABIES VENUSTA K. Kosh. Silver Fir. 



Leaves flat, straight, lanceolate iy 2 — 214 in. long, y 8 in. wide, 

 liesin duets small, ventral, touching epidermis, lined with 2 lay- 

 ers of thin walled cells. 



Vascular bundles — surounded by a slight bundle sheath of loose, 

 round cells ; heavy walled irregular cells between bundles, lig- 

 nified ; phloem extending far around the sides of bundles. 



Hypodermal cells present in double or triple layers below epi- 

 dermis around entire periphery, except along stomata bands, 

 strongly lignified ; heavy layer of cutin over epidermis. 



Stomata on lower surface only in bands of 8-16 rows each side 

 of mid-rib. 



Material from California. 



Plate LX. 

 Figure 1. — Section of leaf of Abies venusta. 



Figure 2. — Section through lower epidermis and stoma of leaf 

 of Abies venusta. 



Figure 3. — Section through epidermis and resin duct of Abies 

 venusta. 



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

 venusta. 



