104 SILVA OF NORTH AMERICA. SAPINDACE. 
first warm days of the late winter or early spring, and long before the appearance of the leaves, which 
do not unfold until the fruit is nearly grown. The calyx is slightly five-lobed, more or less pubescent 
on the outer surface, long and narrow in the sterile, and short and broad in the fertile flower. There 
are from three to seven stamens with slender filaments which in the sterile flower are three times as 
long as the calyx, and in the fertile flower about the length of the calyx. The ovary, which is rudi- 
mentary in the sterile flower, is borne on a narrow disk and is covered, as is the young fruit, with a 
thick coat of pubescence; the styles are united at the base only and have long exserted stigmatic lobes. 
The fruit is borne on slender drooping pedicels an inch and a half or two inches long, and ripens in 
April or May; the samaras vary in length from an inch and a half to nearly three inches, and have thin 
almost straight or conspicuously faleate divergent wings which are sometimes three quarters of an inch 
broad and are prominently reticulate-veined and pale chestnut-brown.’. The seed is half an inch long, 
with a pale reddish brown wrinkled testa and an almost straight embryo with thin foliaceous cotyledons 
and a short radicle; it germinates as soon as it falls to the ground, producing plants with several pairs 
of leaves before the end of the summer. 
Acer saccharinum is found in the north from the valley of the St. John River in New Brunswick 
to southern Ontario; it extends southward through the United States to western Florida, and westward 
to eastern Dakota and Nebraska, to the valley of the Blue River in Kansas, and to the Indian Territory. 
It grows on the sandy banks of clear streams which, with Willows and the Red Birch, it lines in some 
parts of the country, especially in the valley of the Mississippi, where it is one of the largest and most 
common of the river-trees. The Silver Maple is rare in the immediate neighborhood of the Atlantic 
coast or among the high Appalachian Mountains; it reaches its greatest size on the banks of the lower 
Ohio and its tributaries, and there forms one of the most characteristic and beautiful features of the 
forest vegetation. 
The wood of Acer saccharinum is hard, strong, close-grained, and easily worked, but rather brittle ; 
it is pale, faintly tinged with brown, with thick sapwood composed of forty or fifty layers of annual 
growth, and many thin medullary rays. The specific gravity of the absolutely dry wood is 0.5269, a 
It is now sometimes used for floormg and in the manufacture of 
Sugar is occasionally produced from the sap. 
Acer saccharinum appears to have been first distinguished by the Swedish traveler Kalm, who sent 
it to Linneus. It was introduced into English gardens in 1725 by Sir Charles Wager. The Silver 
Maple grows very rapidly in cultivation,’ even on dry soil, and for this reason was planted at one time in 
immense numbers in the northern states as a shade and street tree. 
cubic foot weighing 32.84 pounds. 
cheap furniture. 
When it has grown under favor- 
able conditions it forms a wide-spreading head, beautiful in the play of light and shade through the 
deeply divided leaves dancing with the slightest breath of wind on their slender stems and displaying 
the silvery whiteness of their lower surface. On dry and elevated ground, however, it is not handsome 
except when young; the branches become brittle and are easily broken, and the habit is loose and unat- 
tractive; and the Silver Maple is now much less frequently planted in this country than it was fifty 
years ago. It grows almost as well in Europe as it does in its native country, and numerous varieties 
have been found in American and European nurseries with variously cut and marked leaves and with 
more or less pendulous branches.* 
* When this tree is enticed into expanding its flower-buds by the _a trunk circumference at three and a half feet from the ground of 
succession of a few unnaturally warm days in winter, its fruit is twelve feet six inches in 1837. Fifty-two years later the trunk, 
often entirely destroyed by spring frosts. Not infrequently only which had become hollow and much decayed, measured at the same 
one of the two carpels is developed, the other appearing as a small 
rudiment. 
2 The Silver Maple is a fast-growing tree, even after it has at- 
tained a large size. The great tree on the meadows in Northamp- 
ton, Massachusetts, mentioned by Emerson {Trees Mass. 489), had 
distance from the ground seventeen feet four inches. 
8 Pax (Engler Bot. Jahrb. vii. 180) proposes the following sub- 
varieties for variously cultivated seminal forms of this tree : — 
Var. normale (A. lutescens, Hort., Wittmack, Gartenz. 1883, 513. 
A. macrophyllum, A. Pavia, A. palmatum, A. spicatum). 
