PINACEAE 33 



preceding year. Ovulate aments globular or slightly elongated. Cones spreading: 

 scales at length woody and spreading, each with a dorsal usually spine-armed ap- 

 pendage. Seed samara-like. Spring. PINE. 



Scales of the ovulate aments stout, each with a short tip which scarcely equals the body in length. 

 Resin-ducts of the leaf contiguous to the fibro-vascular bundle. 



Cones elongated, of a conic type and over twice as long as thick when 

 closed, slightly umbonate, the scale-appendages flat or slightly 

 elevated, with decidedly recurved or hooked prickles. 



Cone-scales thin-edged, the appendages flattish, the prickles hooked. 1. P. palustris. 

 Cone-scales thick-edged, the appendages turgid, the prickles slightly 



recurved. 2. P. Caribaea. 



Cones short, of an ovoid type and less than twice as long as thick when 

 closed, prominently umbonate, the scale-appendages elevated, often 

 pyramidal, with nearly straight or decurved prickles. 3. P. Elliottii. 



Resin-ducts of the leaf remote from the fibro-vascular bundle. 

 Cones over 8 cm. long. 



Cones broadly conic when closed and prominently umbonate; scales 

 thick-edged, the appendages projecting little, if at all, beyond the 

 short spine. 4. P. Taeda. 



Cones cylindric-conic when closed, and slightly umbonate; scales 



thin-edged, the appendage projecting far beyond the long spine. 5. P.heterophylla. 

 Cones less than 8 cm. long. 



Cones ovoid or globular-ovoid when closed : leaves 15-25 cm. long, 



about 2 mm. wide. 6. P. serotina. 



Cones narrowly conic when closed: leaves 4-12 cm. long, about 1 



mm. wide. 



Cone-scales readily opening, each with a slender or minute spine 

 towards the front of the appendage, the spine sometimes 

 deciduous or obsolete. 



Cones mainly less than 5 cm. long: scales of the staminate 

 aments erose-toothed at the apex: bark of the trunk rela- 

 tively close and smooth. 7. P. glabra. 

 Cones mainly over 5 cm. long: scales of the staminate 



aments entire: bark of the trunk very rough and shaggy. 8. P. echinata. 

 Cone-scales tardily opening or permanently closed, each with a 



stout spine at the middle or towards the back of the appendage. 9. P. clausa. 

 Scales of the ovulate aments slender, each with a subulate tip several times the 



length of the body. 



Cones conic when closed, ovoid when open: twigs glaucous. 10. P. Virginiana. 



Cones ovoid when closed, globose-ovoid or depressed when open; twigs 



yellow. 

 Scales of the ovulate aments recurved: appendages of the cone-scales 



relatively thin; spine slender, more or less recurved. 11. P. rigida. 



Scales of the ovulate aments ascending: appendages of the cone-scales 



very thick; spines stout, more or less incurved. 12. P. pungens. 



1. Firms palustris Mill. A tree becoming 40 m. tall, irregularly branched 

 above, the bark in large plates: leaves typically in 3's, 20-40 cm. long, bright 

 green, borne in terminal plumes: staminate aments 5.5-8 cm. long: cones 16-25 cm. 

 long, narrowly conic when closed, broadly conic when open, each scale-appendage 

 with a recurved spine: seed 12-13 mm. long, the wing 4.5-5 cm. long. 



In dry or low grounds, Virginia to Florida and Texas, and in the foothills of Georgia 

 and Alabama. GEOKGIA, YELLOW, or LONG-LEAF PINE. 



2. Pinus Caribaea Morelet. A tree usually smaller than P. palustris: leaves in 

 2's or 3's, 18-30 cm. long or shorter, bright green: staminate aments 2.5-4 cm. 

 long: half mature ovulate aments ascending: cones 8-15 cm. long, cylindric-eonic 

 when closed, cylindric or ovoid-cylindric when open: each scale-appendage turgid: 

 seeds 4-7 mm. long, the wing 2-2.5 .xrni. long, or smaller. 



In dry sandy or rocky soil, southern peninsular Florida, and some of the lower keys and 

 near the coast to Georgia and Mississippi. Also in the Bahamas and Cuba. SLASH PINE. 



3. Finus Ellidttii Engelm. A tree becoming 30 m. tall: leaves in 2's or 3 J s, 

 deep green: staminate aments 3.5-5 cm. long: half mature ovulate aments recurved: 

 cones 8-12 cm. long, narrowly ovoid when closed, broadly ovoid when open, each 

 scale-appendage very prominent: seeds 6-8 mm. long, the wing 2-3 cm. long. 



In shallow ponds, swamps and low grounds in the coastal plain, South Carolina to 

 Florida, as far as the Everglade region, and Mississippi. BLUE, or SWAMP PINE. 



4. Pinus Taeda L. A tree becoming 46 m. tall, the dark bark deeply fur- 

 rowed, very rough, exfoliating in coarse plates : leaves in 3 's, glaucous, 15-28 cm. 

 long: cones 10-13 cm. long, narrowly conic when closed, cylindric or conic-cylindric 

 when open, the scale-appendages thick, projecting little, if at all, beyond the small 

 spine: seeds 6-7 mm. long, the wing about 2 cm. long. 



In sandy soil or clay, Delaware to Arkansas, Florida and Texas. LOBLOLLY, or OLD- 

 FIELD PINE. 



5. Pinus heterophylla (Ell.) Sudw. A tree becoming 35 m. tall, the pale 

 bark shallowly furrowed : leaves in 2 's or 3 'a, glaucous, 12-25 cm. long, often stouter 



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