Key to the Genera, 
Leaves linear. 
Leaves in fascicles, I. Pinus, p. 72. 
Leaves alternate. 
a. tetragonal. 2. £iceas Da 79s 
b. flattened. 3. Abies, p. 80. 
Leaves apparently 2-ranked. 
a. bluish-white beneath. 4. Tsuga, p. 83. 
b. green on both sides. 
1, trees. . 5. Taxodium, p. 84. 
2, shrubs. 9. Taxus, p. 94. 
Leaves awl-shaped, 5-ranked. Cryttomerza, p. 89. 
Leaves minute, scale-like. 
Cone-scales basifixed. 6. Thuja, p. 87. 
Cone-scales peltate. 7. Chamecyparis, p. 90. 
Cones berry-like. &. Juniperus, p. 92. 
Leaves ample, fan-shaped. Ginkgo, p. 95. 
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