LEAF INDEX. 31 



SIMPLE-ALTERNATE-SERRATE or Toothed or Crenate. Continued. (II.) 



Veins pinnate, parallel, not much branched, nearly straight to teeth -points. 

 Regularly 2-serrate, mostly oval or ovate, toothed between vein-ends. 



Base oblique, petiole about % in. or less, blade firm, leaves 



2-rowed, veins plain, larger teeth curved forward. (Elms) 



Somewhat rough above, twigs nearly smooth, branches not 



corky. Ulmus Americana 60b 

 Very rough to touch above, downy beneath and on twigs, 



often cordate. Ulmus fulva 60a 



Quite smooth to touch above, branches with narrow corky 



ridges. Ulmus racemosa 60c 



Leaves in alternate pairs on old wood, solitary on new twigs, 



downy beneath. (Birches) 

 Petiole about 1 in., twigs downy, teeth somewhat blunt, bark 



paper 4 -like. Betula papyri/era 68d 



See also (a rare eastern tree, leaves sharply serrate or 



slightly lobed). Betula populifolia 68c 



Petiole < | in., twigs with wintergreen taste, sharply serrate, tapering. 



Bark yellow, in layers, base mostly rounded, dull above. Betula lutea 68b 



Bark dark, not in layers, base often subcordate, shiny 



above. Betula lenta 68a 



Apex tapering, petioles slender, mostly < ^in., blade thin and soft, not glaucous. 

 Length nearly twice width, teeth taper-pointed, small trees. 



Smooth above, veins downy beneath, petiole mostly > ^ in. Carpinus Caroliniana 72a 

 Downy on both sides, petiole mostly < ^ in., bark brown 



and furrowed. Ostrya Virginica 71a 



Broadly ovate, teeth fine, shrubs in dry soil (Hazels) 



Deeply cut between vein-ends, slightly downy beneath. Corylus rostrata 70b 



Not deeply cut between vein-ends, very downy beneath. Corylus Americana 70a 



Not long-tapering, petiole about ^ in. or longer, low ground. (Alders) 



Pale, glaucous and downy beneath, a small tree. Alnus incana 69b 

 Light green beneath, slightly downy, teeth fine, northern 



shrub. Alnus viridis 69a 



See also (petiole long, leaves very large, base oblique and cor- 

 date as below). Tilia Americana lOa 

 Petioles long, mostly 1 in. or more, blade rounded or broadly 



ovate. (Poplars mainly) 

 Petiole round, leaves very large, base oblique and cordate, 



teeth sharp. Tilia Americana ' lOa 

 Petiole round, leaves and buds shining, teeth flat, hardly 



serrate. Populus balsamifera 77c 



Petiole flattened, teeth coarse, notches rounded. Populus grandidentata 77b 



Petioles flattened, teeth fine, abruptly short-pointed. 



Petiole slender, mostly < 2 in. , blade rounded, sometimes 



ciliate. Populus tremidoides 77a 

 Petiole stout, very long, leaves very large, broadly ovate, 



southern. Populus monolifera 77d 



4SEE NEXT PAGE.) 



