SUMMER KEY TO THE SPECIES OF PICEA 



a. Leaves ^-i inch long, sharp-pointed; twigs glabrous, 

 b. Cones 1-2 inches long, maturing in first season ; leaves ill- 

 scented when bruised. P. canadensis, p. 21. 



bb. Cones 3-6 inches long, maturing in second season; leaves 



not ill-scented when bruised P. abies, p. 25. 



aa. Leaves l /$- l /h inch long, blunt-pointed; twigs rusty-pubescent 

 P. mariana, p. 23. 



18 



