PINACE^ 365 



Pinus. 



Key to the Species in Cultivation based on the 

 Characters of the Leaves and Vigorous Young Shoots. 



I. Leaves in Fives. 



Leaf-sheath persistent. 



Young shoots stout, glaucous. Buds cylindric -conic, | in, 



long. — P. Torreyana. 

 Young shoots stout, not glaucous. Buds ovoid, pointed 1 in. 



long. — P. Montezumce. 

 Young shoots slender, glaucous. Buds, leaves and scales as 

 in P. Montezuma). — P. pseudo-strobus. 

 Leaf-sheath partly deciduous, basal portion persisting as a rosette. 

 Leaf speckled with white resinous exudations. — P. aristata. 

 Leaves without resinous exudations. — P. Baljouriana. 

 Leaf-sheath ultimately deciduous. 



Leaves with margins minutely toothed. 

 Young shoots glabrous. 



Shoots glaucous green. Leaves dark or glaucous 

 green, spreading, sometimes slightly bent at base. 

 Cones 6-12 in. long, \\-2 in. wide ; scales thin. — 

 P. excelsa. 

 Shoots olive green, sometimes minutely glandular. 

 Leaves yellowish green, 4-6 in. long, sharply bent 

 at base. Cones 4-7 in, long, 2-3| in, wide ; scales 

 thick, often reflexed at apex, — P. Armandi. 

 Shoots shining green. Leaves 3-4 in. long, not bent 

 at base. — P. Peuke. 

 Young shoots hairy. 



Winter buds with closely pressed scales. 



Shoots with dense, shaggy, orange brown hairs. 



Leaves entire at apex. — P. Cemhra. 

 Shoots with short, dense, often glandular hairs. 

 Leaves twisted in upper haK, blunt at apex. — 



P. monticola. 

 Leaves twisted a complete turn, sharp at apex. — 

 P. Lambertiana. 

 Shoots with minute tufts of hairs below the insertion 

 of the leaves. Leaves very slender. — P. Strobus. 

 Shoots with scattered, minute hairs. Leaves 1-2 

 in. long, curved, usually blunt at apex. — P. 

 par vi flora. 

 Winter buds with scales free at tips. 



Leaves as in P. Cemhra, but teeth continued to the 



blunt tip. — P. Jcoraiensis. 

 Leaves as in P. excelsa. — P. Ayacahuite. 



