24 WOODY PLANTS 



129. Sap milky. . . Rhus, p. 131 



129. Sap not milky. 130 



130. Aromatic. 131 



130. Not aromatic. 133 



131. Bark peeling horizontally around the stem. 132 



131. Bark not as above. . . Lindera , p. 98 



132. Bark pleasantly aromatic, with the odor of wintergreen. . . Betula,p.68 



132. Bark unpleasantly aromatic. . . Prunus , p. 121 



133. Leaf-scars low, straight. . . Rosa, p. 117 



133. Leaf-scars raised, or curved. 134 



134. Lateral buds short-ovoid. 135 



134. Lateral buds elongated-ovoid. 136 



135. Stipule-scars present. . . Betula, p. 68 



135. Stipule-scars absent. . . Pyrus , p. 108 



136, Bud curved, the scales twisted; pith minute, 

 angled. . .Amelanchier, p. 109 



136. Not as above. 137 



137. Buds symmetrical ; pith minute, flattened or 3-angled. . . Betula, p. 68 



137. Without this combination of characters. 138 



138. Buds woolly or gummy. . . Sorbus, p. 109 



138. Buds not as above. 139 



139. Buds oblong or elongated -ovoid. . .Aronia, p. 109 



139. Buds short-ovoid. . . Prunus , p. 121 



140. Stipule-scars encircling the twig. . . Platanus, p. 105 



140. Stipule-scars shorter or none. 141 



141. Leaf-scars nearly encircling the twig. 142 



141. Leaf-scars torn. 144 



142* Sap milky. .. Rhus, p. 131 



142. Sap not milky. 143 



143. Nodes swollen. . . Dirca , p. 154 



143. Nodes not swollen. . . Cladrastis , p. 129 



144. Aromatic; leaf-scars U-shaped when torn. . . Ptelea, p. 131 



144. Not aromatic; leaf-scars irregularly torn. . . Robinia, p. 130 



145. Pith chambered. 146 

 145. Pith continuous. 147 



