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Key of maples

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See also: Comparison of features of maples

1. Compound leaves with 3 to 5 leaflets: Acer negundo (box elder)

1. Simple leaves with palmate veins and lobes: go to 2

 

 

 

 

2. Small trees with flowers in terminal racemes, buds stalked with 2 valvate scales, in the southeast found in the mountains: go to 3

 

2.  Small to large trees with flowers in lateral clusters, buds sessile with 4-8 scales, various habitats: go to 4

 

 

 

3. Leaves coarsely toothed with 5 main veins, twigs and buds hairy, bark not striped, inflorescence erect: Acer spicatum (mountain maple)

3.  Leaves finely toothed with 3 main veins, twigs and buds hairy, bark with white stripes, inflorescence drooping: Acer pensylvanicum (striped maple or moosewood)

 

 

 

4. Leaf margin toothed, wings of fruit tending to form a narrow angle: go to 5

4. Leaf margin entire (smooth), wings of fruit tending to be wide spreading, bark of mature trees with deep furrows and narrow ridges: Acer saccharum  (sugar maple). Go to 6. Acer saccharum subspecies

 

 

 

 

5. Leaves deeply five-lobed with narrow sinuses, one seed and wing of fruit frequently undeveloped, bark of mature trees not deeply furrowed, in our area more frequently planted than wild: Acer saccharinum (silver maple)

5. Leaves having three broad lobes with broad, shallow sinuses, wings of fruit forming a very narrow angle: Acer rubrum (red maple). Note: a hairy wetland variety drummondii is considered by some a separate species.

 

 

 

Subspecies of Acer saccharumThe following taxa are considered subspecies of Acer saccharum by some taxonomists and separate species by others.

6. Leaves yellow-green below: go to 7

6. Leaves green  or gray green below: go to 8

 

7. Leaf blades < 8 cm long, bark white-gray: Acer saccharum ssp. leucoderme or Acer leucoderme (chalk maple)

7. Leaf blades > 9 cm long, bark brown-black: Acer saccharum ssp. nigrum or Acer nigrum (black maple)

 

8. Leaves green and glabrous below except for a few hairs on the veins, lobes of leaves acute: Acer saccharum ssp. saccharum or Acer saccharum (sugar maple)

8. Leaves gray-green and glaucous beneath with hairs on and between veins, lobes of leaves blunt: Acer saccharum ssp. floridanum or Acer floridanum (southern sugar maple)

 

Reference: Wofford, BE and EW Chester. 2002, Guide to the Trees, Shrubs, and Woody Vines of Tennessee. University of Tennessee Press, Knoxville, TN

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