524 IOWA ACADEMY OF SCIENCE 



LARIX LYALLII Pari. Tamarack. 



Leaves 4 angled, 1 — iy 2 in. long. 



Kesin ducts absent. 



Vascular bundle surrounded by a definite bundle sheath of 

 round unlignified cells. Lignified cells extending in a band 

 across the vascular cylinder comprise the xylem. 



Hypo-dermal cells present at angles of leaves — those at lateral 

 angles in a double layer — lignified epidermal cells small, round, 

 un-uniform in size and unlignified. 



AValls of parenchyma not deeply unfolded. 



Material from California. 



Plate XL. 

 Figure 1. — Section of leaf of Larix Lyallii. 



Figure 2. — Section through lower epidermis of leaf of Larix 

 Lyallii. 



Figure 3. — Section through lateral angle of leaf of Larix 

 Lyallii. 



Figure 4. — Section of vascular cylinder of leaf of Larix 

 Lyallii. 



