198 TREES IN WINTER 



42. Twigs usually zigzag; pith roundish; buds and twigs mucilaginous 

 when chewed; fruit spherical, woody, about size of |ea, attached to 

 a leaty bract Ldndeii (Tilia) n 416 



42. Twigs nearly straight; pith more or less ' 5-pointed. star-shaped- 

 buds and twigs not mucilaginous when chewed; fruit a large bur! 

 Chestnut (Castanea dentataj p.29(i 



43. 



Buds superposed, at least at some of the nodes; stipule-scars 



absent ; older pith with reddish streaks 



. „ • • • • Redbiid (Cercis canadensis) p.384 



43. Buds never superposed; stipule-scars present; pith without reddish 

 streaks 44 



44. 2-3 scales visible to a bud 45 



44. 4 or more scales visible to a bud 46 



45. Buds stout; buds and twigs mucilaginous when chewed; lenticels 

 not horizontally elongated; fruit spherical, woody, about size of 

 pea, attached to leafy bract Lrinden (Tilia) p.416 



45. Buds narrower, buds and twigs not mucilaginous when chewed* 

 lenticels on stems and branches horizontally elongated; bark often 

 peeling in papery layers; fruit a winged seed-like body borne in 

 catkins Birch (Betula) 104 



46. Bud-scales 2-ranked (i.e. arranged on the bud in 2 longitudinal 

 rows); leaf-scars covered with a smooth corky layer; bundle-scars 

 typically sunken; bark ridged; catkins absent 



,^ •••• , Elm (Ulmus) 138 



46. Bud-scales more than 2-ranked; leaf-scars not covered with smooth 

 corky layer; bundle-scars not sunken; fruit borne in catkins. .. 47 



47 Lenticels horizontally elongated with age; bark on young trunks 

 and branches smooth, not becoming fluted, often peeling into 

 papery layers but not flaky; fruit a flat seed-like body borne in 



catkins; catkins generally present on tree in winter 



Birch (Betula) 104 



47. Lenticels not horizontally elongated; bark flaky or fluted; bud- 

 scales 4-ranked; fruit a nutlet attached to a bract 48 



48. Bark flaky; twigs 1-2 mm. thick; buds usually 3-7 mm. long; 

 nutlet enclosed by a sac-like bract; staminate catkins generally 



abundantly present in winter 



Hop Horubeam (Ostrya virginiana) p.276 



48. Bark smooth, close, sinewy-fluted; twigs about 1 mm. or less 

 thick; buds usually 2-4 mm. long; nutlet attached to flattish, 

 toothed bract; staminate catkins enclosed in enlarged scaly buds, 



therefore no catkins visible on tree in winter 



American Hornbeam (Carpimcs caroliniana) p.2/78 



49. Buds clustered at tips of vigorous shoots; terminal bud not greatly 

 larger than others of the cluster 50 



49. Buds not clustered at tips of vigorous shoots, or if slightly clus- 

 tered, then terminal bud much larger than others of the cluster 53 



50. Bundle-scars numerous, scattered; pith regularly 5-pointed, star- 

 shaped Oalc (Quercus) 109 and 120 



50. Bundle-scars 3; pith not 5-pointed, star-shaped 51 



51. Terminal bud absent, but leaving a terminal scar on twig 



Plum (Prunus) 150 



51. Terminal bud present 52 



52. Buds woolly at least at tip; collateral buds generally present 



.• Peach (Prunus Persica) p.27S 



52 Buds smooth; collateral buds generally absent 145 



53. Buds stalked 54 



53 Buds not stalked 56 



54. Buds bright yellow dotted, often superposed 



Bitternut (Carya cordiformisj p.274 



54. Buds not bright yellow dotted, not superposed 55 



55 Buds always stalked, blunt; stipule-scars present; catkins present 

 in winter Alder (Alnus) p.292 



