2 TREES OF NORTH AMERICA 



Branchlets not roughened by leaf-bases. 



Leaves stalked, flattened ; bracts of the cone 2-lobed, aristate, longer 

 than the scales. 5. Pseudotsuga. 



Cones erect, theix scales deciduous from the axis, longer or shorter than the 

 bracts. 



Leaves sessile, flat or 4-sided. 0. Abies. 



Scales of the pistillate flowers without bracts ; ovules and seeds borne on the face of minute 

 scales adnate to the base of the flower-scales, enlarging and forming the scales of the 

 cone. 



Taxodi^. Scales of the pistillate flowers numerous, spirally arranged, forming a woody 

 cone ; ovules erect, 2 or many under each scale ; leaves linear, alternate, often of 2 

 forms {deciduous in Taxodium). 



Ovules and seeds numerous under each scale ; leaves persistent. 7. Sequoia. 



Ovules and seeds 2 under each scale ; leaves mostly spreading in 2 ranks, decidu- 

 ous. 8. Taxodium. 

 CuPKESSiNBiE. Scales of the pistillate flower few, decussate, forming a small cone, or 

 rarely a berry ; ovules 2 or many under each scale ; leaves decussate or in 3 ranks, 

 often of 2 forms, usually scale-like, mostly adnate to the branch, the earliest free 

 and subulate. 



Fruit a cone ; leaves scale-like. 



Cones oblong, their scales oblong, imbricated or valvate ; seeds 2 under each 

 scale, maturing the first year. 



Scales of the cone 6, the middle ones only fertile ; seeds unequally 2-winged. 



9. Libocedrus. 

 Scales of the cone 8-12 ; seeds equally 2-winged. 10. Thuya. 



Cones subglobose, the scales peltate or wedge-shaped, maturing in one or two 

 years ; seeds few or many under each scale. 



Fruit maturing in two seasons ; seeds many under each scale. 



11. Cupressus. 

 Fruit maturing in one season ; seeds 2 under each scale. 



12. Chamaecyparis, 

 Fruit a berry formed by the coalition of the scales of the flower ; ovules in pairs 

 or solitary ; flowers dioecious ; leaves decussate or in 3's. 



Leaves subulate or scale-like, often of 2 forms. 13. Juniperus. 



1. PINUS, Duham. Pine. 



Trees or rarely shrubs, with deeply furrowed and sometimes laminate or with thin 

 and scaly bark, hard or often soft heartwood often conspicuously marked by dark 

 bands of summer cells impregnated with resin, pale nearly white sapwood, and large 

 branch-buds formecj during summer. Leaves needle-shaped, clustered, the clusters 

 borne on rudimentary branches in the axils of scale-like primary leaves, inclosed in 

 the bud by numerous scales lengthening and forming a more or less persistent sheath 

 at the base of each cluster. Staminate flowers clustered at the base of leafy growing 

 shoots of the year, each flower surrounded at the base by an involucre of 3-6 scale- 

 like bracts, composed of numerous^sessile anthers, imbricated in many ranks and sur- 

 mounted by crest-like nearly orbicular connectives ; the pistillate subterminal or 

 lateral, their scales in the axils of non-accrescent bracts. Fruit a woody cone matur- 

 ing at the end of the second or. rarely of the third season, composed of the hardened 

 and woody scales of the flower more or less thickened on the exposed surface (the 

 apophysis), with the ends of the growth of the previous year appearing as terminal 

 or dorsal brown protuberances or scars (the umbo). Seeds usually obovate, shorter or 



