Class 1. GYMNOSPERMAE. Naked-seeded Plants. 

 Family 1. PINACEAE. Pine Family. 



Leaves several together (in one species solitary), surrounded by a sheath at the base; 

 cones maturing the second year. 

 Cone-scales with dorsal, usually splne-artned appendages. 



Seeds with elongated wings attached to the seeds when they fall: leaves mostly 



with two flbro-vascular bundles. 1. Pinds. 



Seeds with narrow or rudimentary wings, which remain attached to the scales 

 when the seeds fall; leaves with a single flbro-vascular bundle. 



2. Oahyopitts. 

 Cone-scales with inconspicuous terminal unarmed appendages. 



Seeds with rudimentary wings attached to the scales; cones subsessile, spreading. 



3. Apinus. 



Seeds with well-developed wings, which remain attached to the seeds; cones dis- 

 tinctly stalked, pendulous. 4. Stbobtjs. 

 Leaves not surrounded by sheaths; cones maturing the first year. 



Leaves in fascicles at the ends of short branches, deciduous. 5. L VRix. 



Leaves scattered along the branches, persistent. 



Branches smooth, not roughened by persistent leaf-bases. 



Cones erect, their scales and bracts deciduous from the persistent axis; leaves 



sessile with circular leaf-scars. 6. Abies. 



Cones pendulous, their scales and bracts persistent; leaves petioled with trans- 

 versal oval leaf-scars. 7. PaBUDOTSDOA. 

 Branches roughened by persistent leaf-bases (sterigmata). 



Leaf-blades petioled with a single dorsal duct; anthers opening transversely; 

 seeds with resin-vesicles. 

 Leaves flat, with stomata only on the lower side, 2-ranked by twisting of 



the petioles; cones small, drooping. 8. TSUGA. 



Leaves not much flattened, keeled on the lower side, with stomata on both 

 sides, spreading in all directions; cones elongated; erect at least at first. 



9. Hbspebopeuce. 



Leaf-blades sessile, with two lateral ducts, in ours 4-augled and spreading in 



all directions; anthers opening longitudinally; seeds without resin-vesicles. 



10. PICEA. 



1. PINUS (Toum.) L. Hard Pines, Pitch Pines. 



Leaves in 4's or 5's, with soUtary fibro-vascular bundles and more or less deciduous 



sheaths; spines ofthe cone-scales long and slender. 1. P. aristaia. 



Leaves in 2's or 3's, with usually two flbro-vascular bundles and persistent sheaths; spines 

 of the cone-scales short or none. 

 Cones 6-15 cm. long and 5-6 cm. in diameter; leaves 8-25 cm. long. 



Leaves 12-25 cm. long; cones 8-15 cm. long, elongated-ovoid. 2. P. ponderosa. 



Leaves8-15cm. long; cones 6-9 cm. long, rounded-ovoid. 3. P. scopulorum. 



Cones 3-5 cm. long and about 3 cm. in diameter. 



Cones spreading, or somewhat reflexed ; scales with evident dorsal spines. 



4. P. Murrayana. 

 Cones erect, more or less incurved; scales unarmed or nearly so, at least at matur- 

 ity. 5. P. Banksiana. 



2. CARYOPITYS Small. Nut-pines, Pinons. 



Cones about 3 cm. long; leaves usually in pairs, seldom in threes. 1. C. cdulis. 



Cones 4-5 cm. long; leaves singly or sometimes in pairs. 2. C. monophylla. 



3. APINUS Necker. Cembra Pines. 



Cones 8-15 cm. long; scales neither much thickened nor impressed around the scar, 

 spreading at maturity. 1. A. flexilis. 



Cones 5-8 cm. long; scales much thickened and impressed around the terminal scar, 

 remaining closed. 2. A. albicaulis. 



4. STROBUS Opiz. White Pines. l. S. monticola. 



6. LARIX (Tourn.) Adans. Larch, Tamarack. 



Cones 1-2 cm. long, subglobose; their scales few, longer than the bracts; leaves 3-angled. 



1. L. laricina. 

 Cones 2-4 cm. long, ovoid; their scales numerous, shorter than the bracts. 



Leaves triangular; branches soon becoming glabrate. 2. L. occidenlalis. 



Leaves quadrangular; branchlets tomentose. 3. L. Lyallii. 



6. Abies (Toum.) Hill. Fir, Balsam. 



Resin-ducts of the leaves within the soft tissues, remote from the epidermis. 

 Bracts longer than the cone-scales ; leaves dark green above, pale beneath. 



1. A. balsamea. 

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