316 YEW : SPRUCE, ETC. 



Leaves flat, linear or linear-falcate, solitary and scattered, 

 persisting 3 4 years, the upper and lower on lateral 

 branches twisted into the horizontal plane ; dark shining 

 green above, pale beneath with prominent midrib, acute, 

 2 4 cm. x 1 2 mm. Petiole rather well marked. Dying 

 leaves yellow. Stomata on the lower surface. Venation 

 simple. Vascular bundle undivided. 



Leaves more acicular, and hardly or 

 not at all twisted into the pseudo- 

 distichous position. Shoots resinous. 



jj Leaves quadrangular in section, and 

 almost equally disposed round the 

 shoots, acute and pungent. Endo- 

 dermis icell defined. Leaf -base pro- 

 m inent. 



Picea excelsa, Link. Spruce (Fig. 123). Tall Fir, 

 with pseudo-whorled branches, and distichous twigs, 

 sweeping downwards and forwards. Leaves spirally dis- 

 posed, solitary but crowded, persisting 5 7 years, twisted 

 forwards, especially above, and with a slight tendency to 

 pseudo-distichy in 2 3 ranks below ; leaf-base narrowed 

 to a short petiole, inserted on a prominent angular cushion. 

 Tetragonal, shining green, with very fine stomatal lines on 

 all surfaces ; rough, acute or mucronate and even pungent, 

 about 1 3 cm. x 1 mm. Palisade layer not distinct above 

 and below. Venation simple. Vascular bundle undivided. 

 Dying leaves yellow. 



# Leaves flat, with two silvery stomatal 

 lines beneath. Leaf -base not promi- 

 nent. 



Pseudotsuga Douglasii. Douglas Fir (Fig. 124). Tall 

 Fir with characters intermediate between the Spruces 

 and Silver Firs, with leaves more pointed and falcate 



