INDEX TO THE ARTIFICIAL KEYS
Summer Keys:
Key to the genera, [xxi].
Key to the species of Acer, [172].
Key to the species of Aesculus, [194].
Key to the species of Betula, [84].
Key to the species of Carya, [66].
Key to the species of Catalpa, [222].
Key to the species of Cornus, [202].
Key to the species of Fraxinus, [210].
Key to the species of Juglans, [60].
Key to the species of Picea, [18].
Key to the species of Pinus, [4].
Key to the species of Populus, [44].
Key to the species of Prunus, [152].
Key to the species of Pyrus, [142].
Key to the species of Quercus, [96].
Key to the species of Salix, [34].
Key to the species of Ulmus, [122].
Winter Keys:
Key to the genera, [xxvii].
Key to the species of Acer, [174].
Key to the species of Aesculus, [195].
Key to the species of Betula, [85].
Key to the species of Carya, [67].
Key to the species of Catalpa, [223].
Key to the species of Cornus, [203].
Key to the species of Fraxinus, [211].
Key to the species of Juglans, [61].
Key to the species of Picea, [19].
Key to the species of Pinus, [5].
Key to the species of Populus, [45].
Key to the species of Prunus, [153].
Key to the species of Pyrus, [143].
Key to the species of Quercus, [98].
Key to the species of Salix, [34].
Key to the species of Ulmus, [123].