﻿70 The New York State College of Forestry 



TWIG KEY TO THE SPECIES — (Continued) page 



25. Leaf-scars connected by a transverse line ; terminal bud present 26 



26. Ultimate twigs densely velvety-pubescent Fraxinus pennsylvanica 323 



26. Ultimate twig* essentially glabrous 27 



27. Upper edge of leaf-scar concave or notched; terminal buds obtuse 



Fraxinus americana 327 



27. Upper edge of leaf-scar essentially straight 28 



28. Buds rusty-brown; ridges of mature bark not spongy-corky 



Fraxinus pennsylvanica, var. lanceolata 331 

 28. Buds essentially black ; ridges of mature bark spongy-corky . Fraxinus nigra 333 



29. Bud-scales of axillary buds 1-3 pairs 30 



29. Bud-scales of axillary buds 4- many pairs 34 



30. Axillary buds covered by the persistent bases of petioles. .Cornus florida 315 



30. Axillary buds not covered by the persistent bases of petioles 31 



31. Buds scurfy Viburnum Lentago 341 



Viburnum prunif olium 3 13 



31. Buds not scurfy 32 



32. Line connecting upper leaf-scars straight or notched; bud-scales 2 pairs; 



pith brownish 33 



32. Line connecting upper leaf-scars acute or ligulate; bud-scales 3 pairs; pith 



whitish Acer Negundo 301 



33. Terminal bud smooth and lustrous; young bark with longitudinal white lines. 



Acer pennsylvanicum 289 

 33. Terminal bud with grayish appressed pubescence; young bark without white 



lines Acer spicatum 2 91 



34. Buds acute, brownish; accessory buds lacking 35 



34. Buds obtuse, reddish ; accessory buds usually present 36 



35. Buds slightly puberulous Acer saccharum 293 



35. Buds hoary-pubescent Acer saccharum, var. nigrum 295 



36. Bud-scales usually apiculate; twigs with rank odor when broken 



Acer saccharinum 297 



36. Bud-scales rarely apiculate; twigs without rank odor when broken 



Acer rubrum 293 



37. Terminal bud absent 38 



37. Terminal bud present 64 



38. Stipule-scars absent 39 



38. Stipule-scars present 50 



39. Bundle-scars 5- many (often nearly confluent in Osage Orange) 40 



39. Bundle-scars 1-3 (distinct) 45 



40. Leaf-scars deeply V-shaped, nearly surrounding the bud; buds densely 



tomentose 41 



40. Leaf-scars semicircular to heart-shaped, not extending more than half-way 



around the bud 43 



41. Twigs glabrous, usually glaucous Rhus glabra 281 



41. Twigs not glabrous -42 



42. Twigs finely pubescent; juice watery Rhus copallina 283 



42. Twigs velvety-hairy; juice milky Rhus typhina 279 



43. Buds superposed, sunk in the bark; pith salmon-pink. . . .Gymnocladus dioica 2j7 



43. Buds not superposed, exposed; pith white or ochraceous 44 



44. Twigs stout, unarmed; pith ochraceous Ailanthus glandulosa 277 



44. Twigs slender, usually armed with axillary thorns; pith white 



Madura pomifera 203 



45. Bundle-scar 1, transversely elongated Diospyros virginiana 325 



45. Bundle-scars 3 46 



46. Buds subpetiolar, at length breaking through the leaf-scars; stipular 



spines usually present Robinia Pseudo-Acacia 273 



46. Buds not subpetiolar; leaf-scars below or partly encircling the buds. . . .47 



47. Leaf-scars deeply V-shaped, partly surrounding the buds 48 



47. Leaf-scars not deeply V-shaped; buds inserted above the leaf-scars. .• 49 



48. Superposed buds distinct, glabrous; twigs often with stout branched 



thorns Gleditsia triacanthos 26 ) 



48. Superposed buds contiguous, pubescent; twigs unarmed, with fetid odor 



when bFoken Ptelea trif oliata 275 



