234 Trees for Shade and Ornament 



compact. A very rapid and persistent grower, and shade-enduring, 

 it is well suited for mixture with deciduous trees, especially the light- 

 foliaged ones. Unfortunately, two pests are troubling it: the Cottony 

 Scale, which is, however, not very detrimental and can be combated 

 (page 151), and the Tortrix (page 165), which destroys leaders, giving 

 rise to unsightly double leaders or candelabra, and is less easily pre- 

 vented. 



P. Lambertiana Dougl. (50), the Sugar Pine, of northern California, 

 a magnificent representative of this group, with darker foliage and enor- 

 mous cones (one to two feet long), is, in the East, hardy as far north as 

 Massachusetts in good, deep soils, but rather a slow grower. Hardly 

 superior to the white pine ornamentally, and probably subject to the 

 same damage. 



P. monticola Don. (51), the Silver Pine of the West. If collected 

 from its Rocky Mountain habitats, it would be hardy, but has hardly 

 any points superior to P. Strobus, except a lighter whitish foliage, from 

 which it derives its name. 



Four foreigners in this group deserve attention: 



P. Koraiensis S. & Z. (52), from Corea and Japan, is a very hardy 

 tree, for small places, with darker, bluish, verj' dense foliage and com- 

 pact habit, superior ornamentally to our white pine. An edible, fine- 

 flavored seed (nut) adds to its interest. 



P. Pence Griseb. (53), from Greece, of similar habit in color as 

 the preceding, is a small tree, growing slowly and forming a narrow 

 conical crown. 



P. excelsa Wall. (54), the Bhutan Pine, from the Caucasus, and 

 P. Ayacahuite Ehrenb. (55), the Mexican White Pine, both with 

 longer bunches of slender needles, somewhat pendulous branches, and 

 loose or open form, are adapted only for southern planting, although the 

 Bhutan pine is semi-hardy in the North. 



P. Cembra Linn. (56), the Swiss Stone Pine, a large tree, also a 

 white pine, lacks grace of foliage, the needles being stiff, and only in 

 the form of the old trees is it superior. It is ver\' hardy, but is of 

 remarkably slow growth, and therefore to be recommended only where 

 a slow grower is wanted. 



YELLOW PINES. This is the largest group of pines, much more 

 varied in ornamental value than the former group, but generally of 

 less value than the white pines, because of the rigidity of foliage, and the 

 stiffer, more straggling habit, and long, awkward stage of development. 



