KEY TO GENERA 21 



80. Pith chambered or excavated. 81 



80. Pith continuous. 83 



81. Buds fusiform, multiple. . . Forsythia, p. 181 



81. Not as above. 82 



82. Twigs green, somewhat 4-sided. . . Euonymus , p. 137 



C2. Twigs terete, hairy, brown or gray. , . Symphoricarpos, p. 189 



83. Soft-wooded shrubs with flaking bark. . . Hypericum, p. 153 



83. Not as above. 84 



84. Leaf-scars 2 mm. or more broad. 85 



84. Leaf-scars less than 2 mm. broad. 88 



85. Buds superposed. 86 



85. Buds not superposed. . . Syringa, p. 181 



86. Leaf-scars connected by lines. . . Cephalanthus , p. 186 



86. Leaf-scars not connected by lines. 87 



87. Shrubs with conspicuous lenticels. . . Chionanthus , p. 183 



87. Trees with moderate lenticels. . . Fraxinus, p. 179 



88. Leaf-scars shriveled. . . Symphoricarpos , p. 189 



88. Leaf-scars distinctly outlined. . . Ligustrum , p. 183 



Leaf-Scars Alternate 



89. Climbing or scrambling. 90 



89. Not climbing. 103 



90. Climbing by tendrils or aerial roots. 91 



90. Twining or scrambling, without aerial roots or tendrils. 95 



91. With tendrils. 92 



91. With aerial roots (Caution! Poison Ivy). . . Rhus, p. 131 



92. Tendrils borne on the persistent leaf -base; 

 stems green. . . Smilax ,p. 45 



92. Tendrils opposite the leaf- scars. 93 



93. Tendrils ending in flat disks. . , Parthenocissus , p. 147 



93. Tendrils not ending in disks. 94 



94. Pith somewhat chambered. . . Ampelopsis , p. 147 



94. Pith continuous. . . Vitis , p. 147 



95. Leaf-scars linear or U-shaped. 96 

 95. Leaf-scars not as above. 97 



