342 NEW ENGLAND TKEES IN WINTER. 



153. Leaf-scars narrow, V-shaped, nearly encircling the buds; cut twig 

 showing milky juice 154 



153. Leaf-scars broader; inversely triangular to broadly crescent- 

 shaped; twig with watery juice and resinous taste 



Dwarf Sumach (Rhus copallina) under Comparisons p.526 



154. Twigs densely hairy Staghoru Sumach (Rhus typhina)p.52S 



154. Twigs smooth 



Smooth Sumach (Rhus glabra) under Comparisons p.526 



THE MAPLES 

 Acer. 



Leaf-scars opposite, narrow U or V-shaped; bundle-scars conspicuous, 

 typically 3, equidistant, though sometimes each of these becomes 

 compounded; fruit winged, in pairs. 



155. Adjacent edges of leaf-scars meeting and prolonged upward into 

 a conspicuous tooth 156 



155. Adjacent edges not meeting, therefore not forming a tooth .... 158 



156. Buds white-downy, collateral buds generally present, twigs gener- 

 ally with a bloom Box Elder (Acer Negundo)i*.Z4G 



156. Buds smooth, collateral buds never present, twigs without 

 bloom 157 



157. Buds with only one pair of scales visible, older branchlets white- 

 streaked Striped Maple (Acer pennsylvanicumJT?.*t32 



157. Buds with several pairs of scales visible, branchlets not white- 

 streaked Norway Maple (Acer platanoides) p.542 



158. Outer single pair of bud-scales equalling the bud in length, their 

 edges meeting and enclosing the bud, therefore generally only one 

 pair of scales visible; pith brown; shrubs or at the most small 

 trees 159 . 



158. Outer pair of scales shorter than bud, their edges not meeting, 

 therefore several pairs of scales visible; trees 160 



159. Buds and twigs stout, smooth; young bark with longitudinal white 

 lines Striped Maple (Acer pennsylvanicum,'v-53% 



159. Buds and twigs more slender, both buds and twigs white-downy, 

 white lines absent from bark. Mountain Maple (Acer spicatum)p.534 



160. Buds brown, narrow, sharp-pointed, generally 4-8 pairs of closely 



over-lapping scales visible, collateral buds absent 



Sugar Maple (Acer saccharum)p.53G 



160. Buds red or green, broader, blunt-pointed, fewer scales visible 161 



161. Terminal buds small, red, generally under 5 mm. long and not 

 distinctly larger than lateral buds; collateral buds generally 

 present; pith pink; native trees 162 



161. Terminal buds large, stout, generally over 5 mm. long and gener- 

 ally distinctly larger than lateral buds; collateral buds never 

 present; European trees 163 



162. Broken twigs with rank odor, bark falling away in large, thin 

 flakes on old trees Silver Maple (Acer saccharinum)p.538 



162. Broken twigs without rank odor, bark rough on old trees but gen- 

 erally not flaking in large thin scales 



Red Maple (Acer rubrum) p.54O 



163. Buds red, inner scales covered with rusty wool; adjacent edges of 

 leaf-scars meeting and forming a slight projection; bark close- 

 ridged, not flaky Norway Maple (Acer platanoides 'p.542 



163. Buds green, inner scales white-woolly, edges of leaf-scars not 



meeting; bark flaking off in squarish scales 



Sycamore Maple (Acer Pseudo-Platanus) p.544 



