308 THE CULTIVATED EVERGREENS 



cylindric, slender, slightly curved, 5-11 inches long, yellowish-brown; scales 

 pointed by the slightly thickened, sometimes recurved umbo; seed red-brown, 

 mottled with black, ]/i inch long. British Columbia to Idaho and California. 

 — Introduced to Great Britain in 1851. Hardy as far north as Massachusetts. 

 Very similar in its general appearance to the white pine but of narrower and 

 denser habit. 



12. P. Strobus, L. {Strobus Strobus, Small). White P. Fig. 81 and Plate 

 IV. Attains 100, occasionally 150 feet in height, with horizontal branches 

 in regular whorls forming a symmetrical open pyramid; in old age the head 

 is usually broad and open and often very picturesque; bark on young stems 

 thin and smooth, green tinged with red, on old trunks thick and deeply 

 divided into broad connected ridges covered with small, appressed, purplish 

 scales; branchlets greenish or light greenish-brown, glabrous or slightly 

 puberulous; winter-buds ovoid, acuminate: leaves soft, bluish-green, 2-4 

 inches long (or 33^-5) : cones on stalks 3^-1 inch long, cylindric, slender, 

 often curved, 2-4 inches long, with oblong-obovate scales; seed red-brown, 

 mottled with black, 3 lines long. Newfoundland to Manitoba, south to 

 Georgia, Illinois, and Iowa. — Introduced to France before 1553 and to 

 England about 1705. Hardy as far north as Canada and one of the most 

 valuable ornamental pines for the eastern States; it is of rapid growth, 

 symmetrical when young, picturesque in old age: no tree is better adapted 

 to break up the monotonous sky-line of plantations in northern parks. 

 There are a number of garden forms of which the following are occasionally 

 seen in gardens. 



Var. glauca, Beiss. A form with light bluish-green foliage. 



Var. nana, Knight (var. pygrrujea, Hort.). Dwaef White P. A dwarf, 

 compact, round bush with short leaves. A neat and handsome form. 



Var. fastigiata, Beiss. (var. pyramidalis, Hort.). A form with ascending 

 branches forming a narrow-pyramidal or nearly columnar head. 



Var. prostrata, Mast. A dwarf procumbent form with diffuse branches 

 trailing on the ground. 



Section 11. Parcembra 



Cone-scales with dorsal umbo; scales of the young cone mucronate or 

 aristate: leaves with marginal resin-ducts. 



Group 4. Cembroides 

 Seeds wingless; cones ochre-yellow to deep red-orange: leaf -sheath gradu- 

 ally deciduous (persistent in the Mexican P. Nelsonii, Shaw.). 



13. P. cembroides, Zucc. (P. osteosperma, Engelm.). Mexican Stone P. 

 Small tree, usually not over 20 feet tall, with stout spreading branches forming 



