CONIFERS 6 



longer than their wings; outer seed-coat crustaceous or thick, hard, and bony, the 

 inner membranaceous; cotyledons 3-18, usually much shorter than the inferior radicle. 



Pinus is widely distributed through the northern hemisphere from the Arctic 

 Circle to the West Indies, the mountains of Central America, the Canary Islands, 

 northern Africa, Bermuda, the Philippine Islands, and Sumatra. About eighty species 

 are recognized. Of exotic species the so-called Scotch Pine, Pinus sylvestris, L., of 

 Europe and Asia, the Swiss Stone Pine, Pinus Cembra, L., and the Austrian Pine and 

 other forms of Pinus Laricio, Poir., from central and southern Europe, are often 

 planted in the northeastern states, and Pinus Pinaster, Ait., of the coast region of 

 western France and the Mediterranean Basin is successfully cultivated in central and 

 southern California. Pinus is the classical name of the Pine-tree. 



The North American species can be conveniently grouped in two sections, Soft 

 Pines and Pitch Pines. 



SOFT PINES. 



Wood soft, close-grained, light-colored, the sapwood thin and nearly white ; sheaths of the 

 leaf-clusters deciduous ; leaves with one fibro-vascular bundle. 

 Leaves in 5-leaved clusters. 

 Cones long-stalked. 



Cones bright green at maturity, becoming light yellow-brown, their scales thin, 

 with terminal unarmed umbos. White Pines. 



Seeds shorter than their wings ; leaves 4' long or less. 

 Leaves slender, flexible. 



Cones h'-Q' long. 1. P. Strobus (A). 



Leaves stout, more rigid. 



Cones o'-lV long. 2. P. monticola (B, G). 



Cones 12'-18' long. 3. P. Lambertiana (G). 



Seeds longer than their wings ; leaves slender, ?i^'-^' long. 



Cones 5'-9' long, their scales strongly reflexed at the apex. 



4. P. strobiformis (H). 

 Cones short-stalked. 



Cones green or purple at maturity, becoming yellow-brown, their scales thick with 

 terminal sometimes pointed umbos. 



Seeds much longer than their wings ; leaves 2' long or less, stout and rigid. 

 Stone Pines. 



Cones .S'-IO' long, their scales opening at maturity and losing their seeds. 



5. P. flexilis (F). 

 Cones I'-S' long, their scales remaining closed at maturity. 



6. P. albicaulis (B, F, G). 

 Cones purple at maturity, their scales thick, the dorsal umbos armed with slender 

 prickles ; seeds shorter than their wings ; leaves in crowded clusters, incurved, 

 less than 2' long. Foxtail Pines. 



Cones armed with minute incurved prickles. 7. P. Balfouriana (G). 



Cones armed with long slender piickles.' 8. P. aristata (F, G). 



Leaves in 1-4-leaved clusters. 



Cones globose, green at maturity, becoming- light brown, their scales few, concave, 

 much thickened, only the middle scales seed-bearing; seeds large and edible, 

 their wings rudimentary ; leaves 2' or less, often incurved. Nut Pines. 



Leaves stout, usually in 4-leaved clusters. 9. P. quadrifolia (G). 



Leaves slender, usually in 3-leaved clusters. 10. P. cembroides (H). 



Leaves stout, in 2-leaved clusters. 11. P. edulis (F). 



Leaves stout, usually in 1-leaved clusters. 12. P. monophylla (F, G). 



