TREES. 
. Leaves thin, flat. 77. 
Leaves firm, revolute: fruit fleshy. 
. Fruit dry, winged. 
Fruit fleshy. 
. Buds naked. 
Buds scaly. 79. 
7G. Leaves not lobed. 80. 
. Pith with firmer plates. 
Leaves lobed. 87. 
. Leaves very woolly beneath, entire. 
Leaves not woolly, or if so, toothed. 8&1. 
. Leaves firm and glossy. 82. 
Leaves thin and dull. 83. 
Pith without firmer diaphragms, 
. Leaves whitened beneath. 
Leaves not whitened unléss by tomentum. 
. Without end-bud. 
With a terminal bud. 85. 
. Buds elongated. 8&6. ; 
Buds _ short. 
. Buds woolly. 
Buds not woolly. 
. Leaves pinnately lobed. 
Leaves palmately lobed. 
Compound. 
. Leaves only once compound. &o. 
Leaves often or always bipinnate. 103. 
. Leaflets 3, close together. 
Leaflets several, distinctly pinnate. go. 
Symplocos. 
Halesia. 
Diospyros. 
Rhamnus. 
Cydonia. 
Nyssa. 
Oxydendrum. 
Cornus. 
84. 
Prunus. 
Pyrus. 
. Sorbus. 
Amelanchier. 
Sorbus. 
Liquidambar. 
Laburnum 
. Twigs stout, with large continuous colored pith. 91. 
Twigs moderate, or pith chambered or pale. 93. 
. Leaves with nectar glands: end-bud deciduous. Ailanthus. 
Leaves not gland-bearing. 92. 
. End-bud present. Cedrela. 
- End-bud absent. Gleditsia. 
. Pith chambered, with thin brown plates. 94. 
Pith continuous or at most occasionally fissured. 95. 
