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Illustrated 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:
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
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
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 saccharum. The 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