N. aquatica, Marsh.
The cotton gum is draped in cottony white down as the new shoots start and the leaves unfold in spring. In midsummer this down persists in the leaf-linings, lightening the dark green of the tree-tops. The dark blue fruits of this species have no culinary value. The wood is used for crating material. The tree reaches its maximum height—one hundred feet—in the cypress swamps of Louisiana and Texas, its abundant, corky roots adapting it to its habitat.
The Sweet Gum
Liquidamber styraciflua, Linn.
The sweet gum is a tall tree with a straight trunk, four to five feet in diameter, with slender branches covered with corky bark thrown out in wing-like ridges. At first the head is regular and pyramidal, but in old age it becomes irregularly oblong and comparatively narrow. The bark is reddish brown, deeply furrowed between rough scaly plates, marked by hard, warty excrescences.
The leaves are lobed like a maple's, but more regularly, so as to form a five-pointed star. Brilliant green in summer, they become streaked with crimson and yellow. Wherever these gum trees grow, the autumn landscape is painted with the changeful splendor of the most gorgeous sunset. "The tree is not a flame, it is a conflagration!" Often along a country road the rail fence is hidden by an undergrowth of young gum trees. Their polished star leaves may pass from green into dull crimsons and then into lilacs and so to brown, or they may flame into scarlets and orange instead. Always, the foliage of the sweet gum falls before it loses its wonderful colors.
The flowers of the sweet gum are knobby little bunches; the swinging balls covered with curving horns contain the winged seeds, small but shaped like the key of the maple. One recognizes the gum tree in winter by these swinging seed-balls, an inch in diameter, like the balls of the buttonwood, except that those are smooth. (See illustrations, [pages 102-103].) The best distinguishing mark of sweet gums in winter are the corky ridges on the branches, and the star-shaped leaves under the trees. Sweet gum sap is resinous and fragrant. Chip through the bark, and an aromatic gum soon accumulates in the wound. The farther South one goes, the more copious is the exudation. In Mexico a Spanish explorer described, in 1651, "large trees that exude a gum like liquid amber." This is the "copalm balm" gathered and shipped each year to Europe from New Orleans and from Mexican ports. The fragrant gum, storax or styrax, derived from forests of the oriental sweet gum in Asia Minor, is used as incense in temples of various oriental religions. It blends with frankincense and myrrh in the censers of Greek and Roman Catholic churches. It is used in medicines also, and as a dry gum is the standard glove perfume in France.
Beautiful and interesting in every stage of growth, our native sweet gums are planted largely in the parks of Europe and are earning recognition at home, through the efforts of tree-lovers who would make the most of native species in ornamental planting.
The name, gum tree, is applied to our tupelos, and to the great tribe of Australian eucalyptus trees, now largely planted in the Southwest.
The Osage Orange