﻿Trees of New York State 55 



LEAF KEY TO THE SPECIES 



PAGE 



1. Foliage persistent through the winter 2 



1. Foliage deciduous 19 



2. Leaves j of an inch or less in width 3 



2. Leaves h of an inch or more in width 17 



3. Leaves in fascicles of 2-5 4 



3. Leaves opposite or in spirals 10 



4. Leaves in fascicles of 5; fascicle-sheaths deciduous Pinus Strobus77 



4. Leaves in fascicles of 2 or 3; fascicle-sheaths persistent 5 



5. Leaves in fascicles of 3 6 



5. Leaves in fascicles of 2 7 



6. Leaves flexible; foliage bluish green; buds obtuse Pinus echinata 85 



6. Leaves rigid ; foliage yellowish green ; buds acute Pinus rigida 79 



7. Leaves 3 or more inches long 8 



7. Leaves not over 3 inches long 9 



8. Leaves serrulate Pinus resinosa 87 



8. Leaves entire Pinus echinata 85 



9. Leaves |-U inches long, serrulate, flexible; buds acute Pinus virginiana 81 



9. Leaves l§-3 inches long, entire, rigid; buds obtuse Pinus Banksiana 83 



10. Leaves in spirals, linear or acicular 11 



10. Leaves opposite, awl-shaped or scale-hke 15 



11. Leaves 4-angled, stomatiferous on all sides; foliage with a prickly feel ... 12 

 1 1. Leaves flattened, with two stomatiferous lines below; foliage without prickly 



feel 14 



12. Twigs glabrous Picea canadensis 91 



12. Twigs pubescent 13 



13. Foliage biuish green Picea mariana 95 



13. Foliage yellowish green Picea rubra 93 



14. Leaves sessile, in falling leaving circular scars Abies balsamea 97 



14. Leaves jointed to short persistent sterigmata, in falling leaving a raised 



scar Tsuga canadensis 99 



15. Sprays not flattened Juniperus virginiana 105 



15. Sprays flattened; branchlets appearing as in one plane IG 



16. Foliage bluish green; median leaves taper-pointed; lateral leaves with 



rounded keel Chamaecyparis thyoides 101 



1(). B'oliage yellowish green; median leaves abruptly pointed; lateral leaves 



with acute keel Thuja occidentalis 103 



17. Leaf-margin with distant spinose teeth Ilex opaca 287 



17. Leaf-margin entire : ■\^ 



18. Leaves 3-4 inches long, flat; midribs impressed above. . .Kalmia latifolia 323 

 18. Leaves 4-11 inches long, the margin revolute; midribs rounded above. . 



Rhododendron maximum 321 

 19. Leaves needle-shaped, borne in many-leaved fascicles on short lateral spurs 



and singly in spirals on the twigs of the season Larix laricina 89 



19. Leaves not needle-shaped 20 



20. Leaves opposite or whorled 21 



20. Leaves alternate 39 



21. Leaves simple • 22 



21. Leaves compound 34 



22. Margin entire or nearly so (rarely sparingly lobed toward the base) . . 23 



22. Margin toothed or sinuately lobed 26 



23. Leaves 2-5 inches long Cornus florida 315 



23. Leaves 5-14 inches long 24 



24. Leaves deeply heart-shaped at the base Paulownia tomentosa 335 



24. Leaves rounded or shallowly heart-shaped at the base .25 



25. Leaves light green, thin, acute at the apex Catalpa bignonioides 337 



25. Leaves dark green, thick, acuminate at the apex Catalpa speciosa 339 



• 26. Leaves pinnately veined, not lobed 27 



26. Leaves palmately veined and lobed 29 



