Trees of Xeir York State 71 



TWIG KEY TO THE SPECIES — (Continued) paob 



40. Buds generally superposed; twigs conspicuously zigzag, dotted with numerous 



minute white Icnticels Cercis canidensis 271 



40. Btids not superposed; twigs not conspicuously zigzag Prunus (plums) 372 



r->Q. Buds sub-petiolar; stipule-scars encircling the twig. Platanus occidentalis 229 



50. Buds not sub-petiolar; .stipule-scars not encircling the twig 51 



51. Bundle-scars in a closed or nearly closed ellipse 52 



51. Bundle-scars scattered or in a single lunate line 53 



52. Buds depressed, chiefly lateral to axillary thorns; twigs essentially gla- 

 brous Madura pomifera 209 



52. Buds acute or acuminate; twigs unarmed, pubescent or scabrous 



Broussenetia papyrifera 211 



53. Visible bud scales 1-3 54 



53. Visible bud scales 4- many 57 



54. Bundle-scars more than 3, irregularly scattered or clustered 55 



54. Bundle-scars 3, in a lunate line 56 



55. Buds conspicuously lopsided; twigs usually zigzag, reddish or olive . Tilia species 381 



55. Buds not conspicuously lopsided; twigs nearly straight, brownish 



Castanea dentata 173 



56. Bud-scale one Salix species 352 



56. Bud-scales several Betula species 357 



57. Bundle-scars more than 3, irregularly scattered or clustered Morus alba 215 



57. Bundle-scars 1-3, in a lunate line 58 



58. Buds chiefly subopposite; leaf-scars in I phyllotaxy. . Rhamnus cathartica 305 



58. Buds distinctly alternate; leaf-scars not in ^ phyllotaxy 59 



50. Bud tips appressed; pith diaphragmed-stuffed Celtis occidentalis 207 



59. Bud tips not oppressed: pith homogeneous 60 



60. Older twigs with numerous short spurs which are provided with a 

 terminal bud and densely covered with leaf-scars; twigs often with 



wintergreen flavor Betula species 357 



60. Twigs without spurs or wintergreen flavor 61 



61. Leaf-scars smooth, covered with a corky layer; bundle-scars depressed. . . .62 



61. Leaf -scars not smooth, without corky layer; bundle-scars raised 64 



62. Bud-tips with long rusty hairs; twigs gray, mucilaginous. . . .Ulmus fulva 201 

 62. Bud-tips without long rusty hairs; twigs, brownish, not mucilaginous. .63 

 63. Buds prickly to the touch; twigs often with corky ridges. . . .Ulmus racemosa 205 

 63. Buds acute but not prickly to the touch ; twigs without corky ridges .... 



Ulmus americana 203 

 64. Buds about j of an inch long; twigs about 1/12 of an inch thick; bark 



hght grayish brown, flaky 0.strya virginima 157 



64. Buds about J of an inch long; twigs about 1/25 of an inch thick; bark 



bluish gray, smooth and fluted Carpinus caroliniana 159 



65. Stipule-scars present 66 



65. Stipule-scars absent 75 



66. Stipule-scars extending one-half way around the stem or more 67 



66. Stipule-scars not extending half way around the stem 69 



67. Visible bud-scales many; pith homogeneous Fagus grandifolia 171 



67. Visible bud-scales 2, united into a hood ; pith diaphragmed-stuffed 68 



68. Buds pubescent; leaf-scars mostly lunate Magnolia acuminata 210 



Magnoha virginiana 217 



68. Buds glabrous; leaf-scars mostly orbicular Liriodendron tuhpifera 221 



69. Bundle-scars scattered; first scale of axillary buds lateral Quercus species 360 



69. Bundle-scars 3 or more in a single lunate line; first scale of axil ary buds 



anterior 70 



70. Terminal buds 5-I inch long, decidedly resinous, fragrant when 



crushed 71 



70. Terminal buds |— | of an inch long, devoid of resin or but slightly 



resinous, not conspicuously fragrant when crushed 72 



71. T^\'igs and bud-scales yellowish Populus deltoides 139 



71. Twigs and bud-scales usually reddish brown Populus balsamifera 135 



Populus candicans 137 



72. Twigs of the season white-tomentose, at least toward the tip 



Populus alba 127 

 72. Twigs essentially glabrous 73 



