2 SILVA OF NORTH AMERICA. conifers. 



monoecious, very rarely androgynous, 3 appearing in early spring. Staminate flowers fascicled at the 

 base of leafy accrescent shoots of the year in the axils of bracts, yellow, orange-color, or scarlet, oval, 

 cylindrical, or more or less elongated, composed of numerous sessile two-celled anthers imbricated m 

 many ranks, their cells parallel, extrorse, opening on the sides longitudinally and surmounted by crest- 

 like transverse semiorbicular or almost orbicular connectives, entire, denticulate, lacerate, or rarely short 

 and tuberculate or dentate, each flower surrounded at the base by an involucre of scale-like bracts 

 varying from three to sixteen, usually definite in number on each species, the two external bracts 

 lateral, strongly keeled on the back ; pollen-grains bilobed, with lateral air sacs. 4 Pistillate flowers 

 subterminal or lateral, solitary, geminate, or clustered, erect or recurved, sessile or pedunculate, borne 

 near the apex of branchlets of the year in the axils of bud-scales, composed of numerous carpellary 

 scales each in the axil of a small bract, spirally disposed in many series, rounded, obtuse and appressed 

 at the apex, or produced into longer or shorter or much elongated subulate often scarious tips, bearing 

 on the inner surface near the base two naked collateral inverted ovules. Fruit a woody pendulous 

 horizontal, or occasionally erect, subglobose oblong or elongated conical symmetrical or, by the greater 

 development of the scales on one side than on the other, oblique woody strobile maturing at the end of 

 the second or rarely of the third season, and persistent on the branch after the escape of the seeds, or 

 on some species remaining closed for many years, composed of the now hard and woody scales of the 

 flower more or less thickened on the free exposed surface terminating in a blunt umbo or acicular with 

 a weak or strong caducous or stout persistent mucro, or furnished with a much thickened elongated 

 often curved or twisted spine ; 5 floral bracts now thickened and corky, much shorter than the scales, 

 partly inclosing the seeds in depressions at the base. Seeds geminate, reversed, attached at the base in 

 shallow depressions on the inner face of the scales, obovate or obliquely triangular, occasionally nearly 

 cylindrical, often somewhat compressed, smooth or frequently slightly ridged or tuberculate below, 

 destitute of resin vescicles, in falling bearing away portions of the membranaceous lining of the scale 

 forming wing-like attachments often several times longer or as long or shorter than the seeds, or 

 reduced to a narrow rim frequently remaining attached to the scale after the f ailing of the seed ; testa 

 of two coats, the outer crustaceous, or thick, hard, and bony, pale gray, yellow-brown, or black, 

 sometimes produced into a narrow wing-like border, the inner membranaceous, light chestnut-brown, 

 and lustrous. Embryo axile in copious fleshy albumen ; cotyledons from three to fifteen or rarely 

 eighteen, 6 usually much shorter than the inferior radicle. 7 



About seventy species of Pinus can now be distinguished. 8 The genus is widely distributed 

 through the northern hemisphere from the Arctic Circle to the West Indies 9 and the highlands of 

 Central America 10 in the New World, and in the Old World to the Canary Islands, which are inhabited 

 by one endemic species, 11 northern Africa, Burma, and the Philippine Islands, where one species 

 occurs, 12 and to the mountains of the Indian Archipelago, where a single species crosses the equator. 13 

 Pine-trees form vast forests on high mountain slopes and maritime plains, and are generally scattered 

 through the forests of deciduous-leaved trees in most northern countries. The principal centres of 

 distribution of Pinus are the western United States, where twenty-one species are recognized, the eastern 

 United States, where thirteen species grow, and the highlands of Mexico, which are often covered with 

 great forests of Pine-trees. 14 In the Old World Pine-trees abound in the regions bordering the Medi- 

 terranean, where there are five species, and constitute great forests on the mountains of central Europe 

 and the plains of northern Europe and Asia. In southern Asia the genus is comparatively poorly 

 represented in number of species, although on some of the outer ranges of the Himalayas the forests 

 are largely composed of Pine-trees. 15 It is widely distributed with a few species through eastern con- 

 tinental Asia, 16 and Pine-trees are common in all the elevated regions of Japan. 17 The genus has 

 representatives in all parts of eastern North America except the basin of the central Mississippi and 

 the elevated plains east of the Rocky Mountains; in the north one species only braves the arctic 

 winter ; four inhabit the St. Lawrence basin and northern New England ; the number increases to five 



