268 



Oligocene, alders in, 116 



buttonballs in, 162 



beeches in, 127 



birches in, 102 



cypress in, 61 



hickories in, 71 



maple in, 221 



oaks in, 138 



poplars in, 91 



sequoias in, 52 



walnuts in, 75 



willows in, 85 

 Oligocene epoch, 8 



geography of, 24 

 Olive family', 225 

 Oreomunnea, range of, 76 



Pacific region, forests of, 33 

 Paleozoic era, 8 

 Paper birch, 98 

 Paraguay tea, 213 

 Pasania, 129 



range of, 142 

 Pea family, 191 

 Pecan hickory, 71 

 Peh-la, 227 

 Persimmon, distribution of, 259 



fossils of, 261 



geologic history of, 257-262 



sketch of, 255 



wood of, 255 

 Petrification, 11 

 Planer tree, fossils of, 154 



range of, 153 



sketch of, 153 



species of, 153 

 Plant impressions, 12 

 Platanus, ancestors of, 159 



in Cretaceous, 158 



size of, 158 



sketch of, 157 

 Pleistocene, alders in, 118 



ash in, 232 



beeches in, 128 



birches in, 103 



cypress in, 64 



gums in, 186 



hazels in, 107 



hornbeam in, 110 



linden in, 238 



map of cypress in, 66 



maple in, 223 



oaks in, 139 



platanus in, 163 



poplars in, 94 



walnuts in, 75 



willows in, 86 

 Pleistocene epoch, 8, 25 

 Pliny, quoted, 157 

 Pliocene, alders in, 118 



ash in, 231 



beeches in, 127 



birches in, 102 



cypress in, 63 



gums in, 186 



hickories in, 71 



hornbeams in, 110 



linden in, 237 



maple in, 223 



oaks in, 138 



platanus in, 163 



poplars in, 92 



sassafras leaves of, 250 



walnuts in, 75 



willows in, 85 

 Pliocene epoch, 8 

 Poison ash, 229 

 Poison ivy, 208 

 Poison oak, 208 

 Pond cypress, 58 

 Poplars, in Greenland, 90 



range of, 89 



sketch of, 88 



species of, 89 

 Populus, 88 

 Possum wood, 255 

 Preservation of plants, 10 

 Prickly ash, 229 

 Privet, 225, 227 

 Pterocarya, range of, 76 

 Pussy willow, 82 



