the thickened parts at the base of which contain the seeds. There is no albumen in the seed, which, when put into the ground, expands into two long thin cotyledons, (_a_ in _fig._ 124) which, if once pointed out, will always be known again instantly. If a ripe seed be opened when quite fresh, the cotyledons or seed leaves will be found within it, fresh, green, and succulent; and these leaves (_a_ in _fig._ 124), which rise above the ground as soon as the seed begins to germinate, differ widely in shape from the true leaves (_b_) which are serrated, and of a much thicker texture. The bracts of the Sycamore (_f_ in _fig._ 123) are thick and leathery, and of a rich dark brown. The leaves are serrated at the margin; and the lower ones are cut into five lobes; but those near the flowers have generally only three lobes (_e_), and in all the leaves, two of the lobes are not so deeply cut as the others. [Illustration: FIG. 124.—YOUNG SYCAMORE.] There are many species of Acer, most of which are tall trees; and they are chiefly distinguished from each other by the shape of the leaves and of the samaras, or keys, the wings of which, in some species, are near together, as shown at _d_ in _fig._ 123, and in others widely apart, as in the common hedge Maple (_A. campestris_), and in the Norway Maples, as shown at _a_ in _fig._ 125. This figure represents the flowers of the Norway Maple (_Acer platanoides_), which are in what botanists call a corymb, and stand erect, instead of drooping like those of the sycamore. The leaves are deeply five-lobed, and the lobes are so coarsely toothed, that the teeth have almost the appearance of lobules. The buds of this plant in winter are large and red, and when they open in spring, the bracts (_b_) curl back over the scales (_c_). The leaves become of a clear yellowish red in autumn, and the whole plant is very ornamental. When a leaf of this tree is broken off, a milky sap issues from the broken petiole or leaf-stalk, which is of an acrid nature; differing in this respect, materially from the sap of the trunk, which is very sweet. Sugar indeed may be made from the sap of the trunk of almost all the Maples; but particularly in America, from that of the Sugar Maple (_Acer saccharinum_). The flowers of the red American Maple (_Acer rubrum_) are red, and as from their colour, and their appearing a fortnight before the leaves, they are very conspicuous, I have given a magnified representation of them in _fig._ 126, that my readers may have an opportunity of examining the male and female flowers from a living tree. In _fig._ 126, _a a_ are male flowers, having no stigmas; and _b b_ are female ones, having no stamens. [Illustration: FIG. 125.—FLOWERS AND SAMARA OF THE NORWAY MAPLE.] [Illustration: FIG. 126.—FLOWERS OF THE RED MAPLE (_Acer rubrum_).]