PINE TREES OF ROCKY MOUNTAIN REGION. 3 



red, yellow, or orange. The female flowers, which produce cones and 

 seed, are small, greenish, scaly, conelike bodies, produced singly or 

 in pairs or larger groups near the ends of young growing shoots. 

 After fertilization of one or both of the two ovules (under each scale) 

 the female flowers develop into small cones during the first season, 

 completing their growth at the end of the second or third summer. 



The fruits of pines are woody, scaly cones, matured in 2 or 3 years. 

 Each of the scales in the central portion of the cone usually bears 2 

 seeds at its base and on the under side. The cones of some pines re- 

 main on the trees only a few weeks after ripening, while those of 

 others persist for many years ; or they may be so firmly attached that 

 finally they become entirely enveloped by the annual diameter growth 

 of the branch or trunk and never leave the tree. Within a few weeks 

 after maturity most pine cones open under the heat of the sun and 

 liberate their seeds. The cones of a few pines, however, may remain 

 closed for several or for many seasons, sometimes opening fully only 

 under the heat of a forest fire. The cones of one of our pines {Pinus 

 aTbicaulis) never open naturally, the seeds not being liberated until 

 the scales rot by contact with the ground. This peculiar retention of 

 the seeds explains in part at least how certain pines often reproduce 

 themselves after the original forest has been killed by fire, since not 

 all of the cones are burned enough to destroy their seeds, which are 

 scattered after the fire. 



Mature cones vary in length, according to the species, from an inch 

 to 2 feet, and in diameter from three-fourths of an inch to 6 or 8 

 inches. The seeds of most pines bear a thin papery wing at one end, 

 the wing assisting greatly in the distribution of the seed (PL I, c, d). 

 In a few species, however, the seeds have only the rudiment of a 

 wing, which remains attached to the cone scales, thus rendering the 

 seed wingless when it is shed (PI. X, e) . The pihon or " nut " pines 

 bear wingless seeds, which, unlike winged seeds, are dependent for 

 their distribution on such accidental agencies as flood waters and 

 mammals. Pine seeds vary in size from one-half that of a kernel of 

 wheat to nearly the size of a small hazelnut. 1 



The pines are among our most important commercial trees. Most 

 of them have straight, unbranched, cylindrical trunks, which furnish 

 large amounts of excellent saw timber. On account of the straight 

 grain, strength, and other qualities of pine timber it is used for 

 nearly every sort of construction work. 



The large quantities of naval stores used in the United States, or 

 exported to> other countries, are derived by distillation from the crude 



1 Pine seeds are the favorite food of many birds, and of squirrels and other rodents, 

 which doubtless consume large quantities. Seeds of the " nut " pines are also gathered 

 extensively by western Indians and settlers for food. Mammals, however, often assist 

 in distributing pine seeds through their habit of caching the -seeds in the ground where 

 those not eaten may later germinate. 



