338 TREES OF MINNESOTA. 
goods, wood type, and engravers’ wood, butter molds, croquet 
sets, crutches, umbrella sticks and canes, kegs, sugar hogsheads, 
churns, measures, faucets, wood screws and gauges charcoal, in 
turnery for handles of tools and clothes pins, and in ship build- 
ing for keels, etc. In the United States shoe lasts and pegs 
are made almost exclusively from this wood. Accidental forms 
in which the grain is beautifully curled and contorted, known 
as “curled maple” and “bird’s-eye maple’ are common, and 
highly prized for cabinet making. The ashes of the wood are 
rich in alkili, and yield large quantities of potash. The wood of 
the Minnesota and Wisconsin Sugar Maple is so very hard and 
uneven in grain that it has not been worked much into lumber, 
and the supply of Hard Maple lumber manufactured here is 
mostly imported from Michigan, where clear stock is more 
plentiful. Maple sugar is almost the exclusive product of this 
tree. It is made by evaporating the sap, which is procured by 
tapping the trees in early spring some weeks before the buds 
begin to swell. About three or four gallons of sap are usually 
required to make a pound of sugar. ‘Two or three pounds of 
sugar per tree is the average yield, but large isolated trees will 
often yield very much more than this. When tapping is prop- 
erly done it does not seriously impair the health of the tree. 
Acer platanoides. Norway Maple. 
Leaves broad, smooth, thin, bright green on both sides, their 
five short taper-pointed lobes set with coarse taper-pointed teeth. 
Flowers numerous, with both sepals and petals distinct, yellow- 
ish, conspicuous, in erect corymbose clusters terminating the 
shoot of the season, or some from lateral buds appearing with 
the leaves. Fruit in drooping clusters, with large divergent 
wings spreading two and one-half to three and one-half inches, 
ripening in autumn. Buds blunt pointed and rather divergent; 
new growth often reddish; juice milky. Resembles the Sugar 
Maple in general appearance, but is easily distinguished from it. 
Its leaves hold green later than other maples, and turn a bright 
yellow in autumn. A round-headed tree attaining a height of 
from thirty to sixty feet. 
Distribution.—Northern and central Murope and Asia. 
Propagation..—By seeds for the species and by budding, graft- 
ing or layering for the varietics. 
