ootka Sound Cypress, 195.

Nordmann's Silver Fir, 184.

Northern Prickly Ash, 73.
Scrub Pine, 178.

Norway Maple, 87.
Spruce, 180.

Nut, Bitter, 143.
Hickory, 142, 143.
King, 142.
Mocker, 142, 143.
Pecan, 144.
Pig, 143.

Nut-pine, 178.

Nyssa, 112, 113.

Oak, American White, 153.
Barren, 158.
Bartram's, 152.
Basket, 154.
Bear Scrub, 157.
Black, 156, 158.
Black Scrub, 157.
Box White, 153.
Bur, 153.
Chestnut, 154, 155.
Cow, 154.
English, 158.
Laurel, 158.
Live, 155.
Mossy-cup, 153.
Pin, 156.
Post, 153, 154.
Pyramidal, 159.
Quercitron, 156.
Red, 156.
Rough, 153.
Scarlet, 156.
Scrub, 157.
Shingle, 158.
Spanish, 156, 157.
Swamp, 154, 156.
Turkey, 159.
Water, 157.
Weeping, 159.
White, 153, 154.
Willow, 158.
Yellow, 155, 156.

Oak Family, 144.

Oak-leaved Alder, 148.
Mountain-ash, 102.

Ohio Buckeye, 82.

Old-field Pine, 174.

Oleaceae, 122.

Oleaster Family, 131.

Olive Family, 122.

Orange, Osage, 137.

Oriental Plane, 139.
Spruce, 181.

Osage Orange, 137.

Osmanthus, 125.

Ostrya, 150.

Oxydendrum, 116.

Palmate-leaved Japan Maple, 88.

Papaw, 68.

Paper Birch, 145.
Mulberry, 138.

Parsley-leaved Thorn, 105.

Paulownia, 127.

Peach, 97.

Pear Hawthorn, 106.

Pear-tree, 101.

Pea-tree, 92.

Pecan-nut, 144.

Pepperbush, 117, 118.

Pepperidge, 112.

Persea, 130.

Persimmon, 119, 120.

Phellodendron, 74.

Picea, 179-181.

Pignut, 143.

Pine, Austrian, 175.
Bhotan, 172.
Black, 175.
Cembra, 173.
Chile, 190.
Corsican, 175.
Gray, 178.
Heavy-wooded, 174.
Japan, 176.
Jersey, 177.
Lambert's, 172.
Loblolly, 174.
Long-leaved, 174.
Masson's, 175.
Mountain, 173, 177.
Nut, 178.
Old-field, 174.
Pinon, 178.
Pitch, 174.
Red, 176.
Scotch, 177.
Scrub, 177, 178.
Stone, 173.
Sugar, 172.
Swiss Stone, 173.
Table-Mountain, 177.
Twisted-branched, 177.
Umbrella, 191.
Weymouth, 172.
White, 172, 173.
Yellow, 174,176.

Pine Family, 170.

Pin-oak, 156.

Pinon Pine, 178.

Pinsapo Fir, 186.

Pitch-pine, 174.

Pinus Austriaca, 175.
Banksiana, 178.
Cembra, 173.