PINACEAE 



The Pines 



Characteristics of the Genus Pinus L. 



HABIT, Evergreen trees with straight, unbranched, cylin- 

 drical trunks, and whorled, spreading branches. 



LEAVES. Needle-like; in fascicles or bundles of 1-5; en- 

 closed in bud by 6-12 scales which form a persistent or soon- 

 deciduous basal sheath ; usually with several lines of stomata on 

 each surface; juvenile leaves on young shoots differ in being 

 spirally arranged, single, and scalelike. 



FLOWERS. Monoecious; male,, or pollen-producing, con- 

 sisting of spirally arranged, sessile anthers, yellow, orange, or 

 scarlet; female, or cone- and seed-producing, small, conelike 

 bodies consisting of numerous spirally arranged, 2-ovuled scales, 

 each subtended by a small bract. 



FRUIT. A cone, usually pendent, composed of the hard- 

 ened, woody scales of the flower; scales more or less thickened 

 on the exposed terminal surface (the apophysis) with the ends 

 of the growth of the previous year appearing as a terminal or 

 dorsal, brown protuberance or scar (the umbo), which is often 

 armed with a prickle; maturing in 2 (rarely 3) seasons. Seed: 

 2 borne at the base on inner face of each fertile scale ; with thin, 

 terminal, papery wing or wingless. 



BUDS. Variable in size, shape, and color; covered by fringed 

 or papery-margined overlapping scales; these component scales 

 each protecting a tiny bud which, after the main bud unfolds, 

 develops into a fascicle of leaves or occasionally into a female 

 flower. 



WOOD. Among our most important trees; properties ex- 

 tremely variable; numerous, large, easily visible resin ducts: 

 resinous scent. Some species produce, in addition to lumber, 

 naval stores and edible nuts. 



GENERAL. The largest and most important genus of conifers, 

 including about 80 species widely scattered over the Northern 

 Hemisphere; 36 species are native to the United States and 

 Canada; the North American species can be conveniently 

 grouped into the soft or white pines, and hard, pitch, or 

 yellow pines. 



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