"A maple-tree, prob. so called from its pointed leaves. ex. Sugar maple"-Whitney, 1902

Acer

"A maple-tree, prob. so called from its pointed leaves. ex. Sugar maple"-Whitney, 1902

"A maple-tree, prob. so called from its pointed leaves. ex. Sugar maple"-Whitney, 1902

Acer

"A maple-tree, prob. so called from its pointed leaves. ex. Sugar maple"-Whitney, 1902

Germination of Silver Maple, natural size; merely the base of the fruit, containing the seed, is shown.

Germination of Silver Maple

Germination of Silver Maple, natural size; merely the base of the fruit, containing the seed, is shown.

A class of trees belonging to the genus acer, containing about eighty species, all of which are confined to the north temperate zone.

Maple

A class of trees belonging to the genus acer, containing about eighty species, all of which are confined…

Much magnified small portion of young root of a seedling Maple.

Maple

Much magnified small portion of young root of a seedling Maple.

Cells of young root of a seedling Maple.

Maple

Cells of young root of a seedling Maple.

Surface of a young Maple wood from which the bark has been torn away, showing the bark (on the left) to beginning of pith (on the right), and a medullary ray extending from one to the other.

Maple

Surface of a young Maple wood from which the bark has been torn away, showing the bark (on the left)…

"Accessory buds of box-elder (Negundo). A, front view of group; B, two groups seen in profile." -Bergen, 1896

Maple Buds

"Accessory buds of box-elder (Negundo). A, front view of group; B, two groups seen in profile." -Bergen,…

Lower end of Maple root magnified, the root seen just as root-hairs are beginning to for a little behind the tip.

End of Maple Root

Lower end of Maple root magnified, the root seen just as root-hairs are beginning to for a little behind…

Maple seeds.

Maple Seed

Maple seeds.

Seedling Maple, of the natural size; the root well supplied with root hairs, here large enough to be seen by the naked eye.

Maple Seedling

Seedling Maple, of the natural size; the root well supplied with root hairs, here large enough to be…

A Red Maple seedling with next joint of stem and leaves apparent.

Maple Seedling

A Red Maple seedling with next joint of stem and leaves apparent.

A Red Maple seedling with parts full-grown and bud at apex for further growth.

Maple Seedling

A Red Maple seedling with parts full-grown and bud at apex for further growth.

Here is a representation of two seeds of the maple, with their wings. They always grow in this way, in pairs.

Maple Seeds

Here is a representation of two seeds of the maple, with their wings. They always grow in this way,…

Magnified view of surface of a bit of young Maple wood from which the bark has been torn away, showing the wood-cells and the bark-ends of medullary rays.

Bit of Young Maple Wood

Magnified view of surface of a bit of young Maple wood from which the bark has been torn away, showing…

An illustration of the cotyledon of a maple. A cotyledon is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling.

Cotyledon of a Maple

An illustration of the cotyledon of a maple. A cotyledon is a significant part of the embryo within…

The leaf of a Japanese Maple tree.

Japanese Maple

The leaf of a Japanese Maple tree.

The leaf of a Norway Maple tree.

Norway Maple

The leaf of a Norway Maple tree.

The leaf of a Red or Swamp Maple tree.

Red or Swamp Maple

The leaf of a Red or Swamp Maple tree.

The leaf of a Silver Maple tree.

Silver Maple

The leaf of a Silver Maple tree.

They are among the most prized of trees for park and street planting, and nearly all of them become finely colored in autumn.

Sugar Maple

They are among the most prized of trees for park and street planting, and nearly all of them become…

The leaf of a Sugar Maple tree.

Sugar Maple

The leaf of a Sugar Maple tree.

The leaf of a Sycamore Maple tree.

Sycamore Maple

The leaf of a Sycamore Maple tree.

"1. Acer circinatum. 2. flower of A. campestre; 3. its samara; 4. the same, with the seed laid bare; 5. the embryo unfolded." -Lindley, 1853

Vine Maple

"1. Acer circinatum. 2. flower of A. campestre; 3. its samara; 4. the same, with the seed laid bare;…

The seeds of the Mountain Maple, Acer spicatum, (Keeler, 1915).

Mountain Maple Seed

The seeds of the Mountain Maple, Acer spicatum, (Keeler, 1915).

One of the pair of keys or winged fruits of Red Maple; the seed-bearing portion cut open to show the seed.

Red Maple

One of the pair of keys or winged fruits of Red Maple; the seed-bearing portion cut open to show the…

This shows the axillary buds on a twig of Red Maple, they are opposite like the leaves.

Red Maple Buds

This shows the axillary buds on a twig of Red Maple, they are opposite like the leaves.

Embryo taken out and partly opened.

Red Maple Embryo

Embryo taken out and partly opened.

The seeds of the Red Maple, Acer rubrum, (Keeler, 1915).

Red Maple Seed

The seeds of the Red Maple, Acer rubrum, (Keeler, 1915).

Seed enlarged, and divided to show the crumpled embryo which fills it.

Red Maple Seed

Seed enlarged, and divided to show the crumpled embryo which fills it.

A newly germinated seed of the Red Maple, seed leaves, and the roots.

Red Maple Seedling

A newly germinated seed of the Red Maple, seed leaves, and the roots.

A more advanced seedling of the Red Maple,.

Red Maple Seedling

A more advanced seedling of the Red Maple,.

Seedling with stem joints and pair of leaves.

Red Maple Seedling

Seedling with stem joints and pair of leaves.

Silver maple not pruned since setting out.

Silver maple not pruned since setting out.

Silver maple not pruned since setting out.

Silver maple after severe heading back.

Silver maple after severe heading back.

Silver maple after severe heading back.

A Silver Maple embryo, taken out of the husk; upper part of growing stem cut off.

Silver Maple Embryo

A Silver Maple embryo, taken out of the husk; upper part of growing stem cut off.

The staminate flowers of the Silver Maple, Acer saccharinum, (Keeler, 1915).

Silver Maple Flower

The staminate flowers of the Silver Maple, Acer saccharinum, (Keeler, 1915).

The pistillate flowers of the Silver Maple, Acer saccharinum, (Keeler, 1915).

Silver Maple Flower

The pistillate flowers of the Silver Maple, Acer saccharinum, (Keeler, 1915).

Fruit of Silver Maple, Acer dasycarpum, of natural size, the seed-bearing portion divided to show seed.

Silver Maple Key

Fruit of Silver Maple, Acer dasycarpum, of natural size, the seed-bearing portion divided to show seed.

The seeds of the Silver Maple, Acer saccharinum, (Keeler, 1915).

Silver Maple Seed

The seeds of the Silver Maple, Acer saccharinum, (Keeler, 1915).

Embryo of the seed taken out.

Silver Maple seed

Embryo of the seed taken out.

Silver Maple seed open out, to show the thick cotyledons and the little plumule or bud between them.

Silver Maple Seed Open

Silver Maple seed open out, to show the thick cotyledons and the little plumule or bud between them.

Piece of a stem of Soft Maple, of a year old, cut crosswise and lengthwise.

Piece of Stem from a Soft Maple

Piece of a stem of Soft Maple, of a year old, cut crosswise and lengthwise.

"The maple spot gall, so common on the leaves of the red maple, is made by the fungus-gnat of the order Diptera." — Davison, 1906

Maple spot gall

"The maple spot gall, so common on the leaves of the red maple, is made by the fungus-gnat of the order…

The seeds of the Striped Maple, Acer pennsylvanicum, (Keeler, 1915).

Striped Maple seed

The seeds of the Striped Maple, Acer pennsylvanicum, (Keeler, 1915).

Embryo of Sugar Maple, cut through lengthwise and taken out of the seed.

Sugar Maple

Embryo of Sugar Maple, cut through lengthwise and taken out of the seed.

Pair of samaras of Sugar Maple.

Sugar Maple

Pair of samaras of Sugar Maple.

Embryo of Sugar Maple,(Gray, 1858).

Sugar Maple Embryo

Embryo of Sugar Maple,(Gray, 1858).

Whole embryo of Sugar Maple just beginning to grow.

Sugar Maple Embryo

Whole embryo of Sugar Maple just beginning to grow.

The seeds of the Sugar Maple, Acer saccharum, (Keeler, 1915).

Sugar Maple seed

The seeds of the Sugar Maple, Acer saccharum, (Keeler, 1915).

Leaves - simple; opposite; edge lobed, with the lobes very sparingly and coarsely sharp-toothed or the lower pair entire. Outline - rounded, with three to five lobes, usually five, with the hollows between the lobes and between the coarse teeth rounded. Apex - of the lobes, pointed. Base - heart-shaped or nearly squared. Leaf - dark green above; slightly lighter beneath; smooth or somewhat downy on the ribs; closely resembling that of the introduced "Norway Maple" by lacking the latter's milky-juiced leaf-stem. Bark - light gray, usually smoothish when young, becoming rough and scaly. Flowers - yellow-green and very abundant. April, May.  Fruit - greenish-yellow, smooth, drooping, on thread-like and hairy stems one to two inches long, with wings about one inch long, broad and slightly spreading. September. Found - from Southern Canada through the Northern States, southward along the Alleghany Mountains, and westward to Minnesota, Eastern Nebraska, and Eastern Texas. Its finest development is in the region of the Great Lakes. It grows in rich woods; often it forms "groves," sometimes extensive forests.

Genus Acer, L. (Maple)

Leaves - simple; opposite; edge lobed, with the lobes very sparingly and coarsely sharp-toothed or the…