This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Besides the following, some 8 others occur in southern and western North America. Type species: Acer Pseudo-plātanus L.
Leaves simple, palmately lobed.
Flowers in dense sessile lateral clusters, unfolding before the leaves.
Petals none; ovary tomentose; samaras divergent.
Petals present; ovary glabrous; samaras incurved.
Leaves bright green above, mostly 5-lobed.
Wings of the samara broadened above the middle.
Wings of the samara linear, scarcely broadened above.
Leaves dark green above, mostly 3-lobed.
Leaves densely whitish-pubescent beneath; southern.
Flowers corymbose, lateral, unfolding with the leaves.
Leaves pale and nearly glabrous beneath.
Leaves green and pubescent, at least on the veins, beneath.
Flowers short-pedicelled, erect; shrub or small tree; western.
Flowers racemed, terminal, unfolding after the leaves.
Racemes drooping; leaves finely serrate.
Racemes erect; leaves coarsely serrate.
Acer saccharinum L. Sp Pl. 1055. 1753.
Acer eriocarpum Michx. Fl. Bor. Am. 2: 253. 1803.
A large tree with flaky bark, maximum height of 100°-120° and trunk diameter of 3°-5°. Leaves 4'-6)' long, deeply 5-lobed, the lobes rather narrow, acuminate, coarsely and irregularly dentate, truncate or slightly cordate at the base, green above, silvery. white and more or less pubescent beneath, especially when young; flowers greenish to red, in nearly sessile lateral corymbs much preceding the leaves; calyx obscurely lobed; petals none; fruiting pedicels elongating; stamens 3-6; samaras pubescent when young, divaricate, at length 2' long, the wing often 6" wide.
Along streams, New Brunswick to Florida, west to southern Ontario, South Dakota, Nebraska and Oklahoma. The samaras are frequently unequally developed. Wood hard, strong, light colored; weight per cubic foot 32 lbs. Used for furniture and floors. Maple sugar is made from the sap in small quantities. River-, silver-leaf-, creek-, water- or swamp-maple. Feb.-April.
Acer Pseųdo-Plátanus L., sycamore-maple, with terminal drooping racemes of yellowish flowers with very woolly ovaries, and deeply 3-5-lobed leaves, and Acer platanoides L., Norway maple, with terminal corymbs of greenish yellow flowers appearing with or before the 5-7-lobed leaves, commonly planted, have occasionally escaped from cultivation.