6 PlNACEAE 



merous in individuals forming conifer forests of large extent 

 and furnishing the principal "soft woods" of temperate regions. 

 Largely employed for windbreaks and evergreen effects; char- 

 acteristically trees, but likely to occur in shrubby form. 



PICEA. Spruce. 



Conical evergreen trees with rather soft yellowish-white 

 ductless wood with scattered resin-passages (exceptionally 

 brown and with transversely clustered passages) ; moderate 

 fluted often hairy twigs; small homogeneous pith; 5-ranked 

 usually 4-sided needle-like leaves on raised bases bearing the 

 angled leaf-scars with a single bundle-trace; no stipule-scars; 

 ovoid scaly more or less resinous budg; monoecious catkin-like 

 or cone-like naked flowers; and pendent cones with persistent 

 thin scales each covering 2 winged seeds. 



1. Leaves small, green, blunt. P. orientalis. 

 Leaves mostly longer (20-25 mm.), acute. 2. 



2. Leaves green. 3. 



Leaves pale or whitened. 4. 



3. Not weeping. (European spruce). P. excelsa. 

 Weeping. P. excelsa pendula. 



4. Leaves merely pale. 5. 



Leaves very glaucous. (Blue spruce). P. pungens. 



5. Odor balsamic: cones large (10-18 cm.). P. excelsa. 

 Odor fetid: cones small (scarcely 5 cm.). P. canadensis. 



TSUGA.. Hemlock Spruce. 



Evergreen percurrent trees with ductless brownish wood 

 without resin-passages; slender fluted twigs; small continuous 

 pith; alternate somewhat raised minute half-round leaf -scars 

 with a single bundle-trace; no stipule-scars; round or ovoid 

 with several exposed scales; very small oblong or lanceolate 

 sometimes serrulate short-petioled flat leaves whitened be- 

 neath; monoecious catkin- or cone-like naked flowers 1 ; and 

 small ovoid cones, each thin scale covering 2 winged seeds. 

 1. Trees. 2. 



Prostrate shrub. T. canadensis nana. 



