Farther down, the branches have warty bark, broken into rough, horny plates. This gives the tree its name, "alligator wood." Then the grey of the big branches gives way to the red brown of the trunk; the shallow fissures and scaly ridges give a finer texture to this oldest bark than the limbs give us reason to expect.
In summer time the leaves of the sweet gum are our sure guide to its identity. "Star-leaved gum," it is often called. There is no other tree whose leaf so closely resembles a regular, six-pointed star with one point missing where the petiole is fastened on. These leaf stems are long and flexible—a very important fact in analysing the beauty of the sweet gum tree in full leaf. The large shining blades flutter on their stems, "Continuous as the stars that shine And twinkle in the Milky Way." They fairly dazzle the beholder, as the polished leaves of the tulip tree always do.
But the summer garb of the sweet gum tree is pale and monotonous compared with the radiant beauty of its October foliage. Wherever gum trees grow, there the autumn landscape is painted with the changeful splendour of sunset skies. The leaves do not seem to dry and wither as maples and dogwoods do. They give up their bright green for the most gorgeous shades of red. "The tree is not a flame—it is a conflagration!" Often one sees a fence-row thicket of young gum trees all burning low with dull crimsons as if their fires sullenly smoulder, and might at any moment burst into the clear orange-red flame that consumes a neighbour tree. Afterward, the foliage may turn to those browns and lilac tones assumed by ash trees, but as a rule the ground is littered with the leaves before they fade— they "die like the dolphin." The sap of the sweet gum is resinous and fragrant. It is easy to find this out by crushing a leaf or bruising a twig. Chip through the bark of a tree and an aromatic gum accumulates in the wound. In the Northern States this exudation is scant, but it becomes more plentiful as one proceeds south. The most
copious flow is from trees in Central America. This gum is known to commerce as "copalm balm," large quantities of which are shipped to Europe from New Orleans and from Mexican ports each year. A Spanish explorer in Mexico described in 1651 "large trees that exude a gum like liquid amber." This was the beginning of the trade. Linnus later gave the name "liquid ambar" to the whole genus, which contains four species. Be sides our American tree there is a species in eastern Asia, not yet well known, and a very important species, L. orientalis, which forms forests in Asia Minor. Long before the Christian era the fragrant gum storax, or styrax, of these trees was used as incense in the temples of various oriental religions. Later it had its place also with frankincense and myrrh in the censers of the Greek and Roman Catholic churches. It was used then, as it is now, as a healing balm, as a medicinal drug and as a perfume.
The American gum is believed to have the same properties as the oriental storax, and it is manufactured into medicines, perfumes, and incense. As a dry gum, it is the standard glove perfume in France.
First and last, it is not the products of the sweet gum tree that should first commend it to the American people. It is the tree itself, beautifying by its growth the landscape of which it is a part. More and more we are realising the value of native things in landscape gardening. There is a lesson for the American (who would not learn it at home) as he hunts in European gardens and nurseries for trees to plant on his estate. Among the finest and most valued trees abroad is his own native Liquidanzbar Styraciflua, all the more esteemed because there is no European species.
The name "gum tree" is also applied to our tupelos, and to certain species of Eucalyptus, natives of Australia.