Trees With Winged Seeds - Elms
( Originally Published 1927 )
Elms of sixteen distinct species are native to boreal and temperate regions of the Northern Hemisphere, with this single exception : western North America is without a representative. Europe has three species, two of which extend their range into eastern Asia and northern Africa. Southern and central Asia have their own species. Five are native to our Eastern states. Two European species are in cultivation in the North Atlantic states, especially in the neighborhood of Boston, where they are as familiar as the native species, in street planting.
Elm trees are valuable for shade and for lumber; their wood is hard, heavy, tough, pale in color, often difficult to split. The trees are distinguished from others by their simple, unsymmetrical, strong-ribbed leaves, saw-toothed, short-stalked, always unequal and often oblique at the base of the blade. The flowers, usually perfect, are inconspicuous, and the seeds are flat, entirely surrounded by a thin papery wing, that forms two hooks at the tip. Wind-carried, these seeds have had much to do with the wide distribution of elms.
The White Elm
Ulmus Americana, Linn.
The white or American elm is widely known as a tall, graceful wide-spreading tree, usually of symmetrical, vase shape, with slender limbs and drooping twigs.
It has the rough furrowed bark characteristic of the genus, dark or light gray, with paler branches and red-brown twigs. The leaves are alternate, two to six inches long, broadest near the abruptly pointed apex. Distinctly one-sided at the tapering base, the leaves have a fashion of arranging themselves in a flat spray so as to present almost a continuous leaf area to the sun. One spray overlaps another, and leaves varying in size fit in to fill every little corner 'to which sunlight comes. This "leaf mosaic" is not con-fined to elms alone. It is especially noticeable on the southern border of any dense wood.
Winter offers the best opportunity for the study of tree forms. Our common elm shows at least five different patterns. The first is the "vase form," the commonest and most beautiful. This is best realized by old trees which have had plenty of room. In it the branches spread gradually upward at first but at a considerable height sweep boldly out forming a broad, rounded, or flattened head. Second is the "plume form," in which two or three main limbs rise to a great height before branching, and then break into feathery spray. Trees crowded in woods are likely to take this form. Third, the "oak tree form" shows a horizontal habit of branching, and an angularity of limbs usually more noticeable among oaks, Fourth, the "weeping willow form," where trees have short trunks, from which the branches curve rapidly outward and end in long, drooping branchlets. Fifth is the "feathered elm," marked by a fringe of short twigs which outline the trunk and limbs. This "feathering" is caused by the late development of latent buds. It may occur in any of the tree types just mentioned, but it is more noticeable in individuals of the plume form.
The American elm is very familiar for it grows every-where east of the Rocky Mountains. Not to know this tree is a mark of indifference and ignorance. No village of any pride but plants it freely as a street tree. It is hardy and cheerful, reflecting the indomitable spirit of the pioneer, whom it accompanied by seed and sapling from the Eastern states into the treeless territories of the Middle West. With him the tree seized the land and made it yield a living. Elms, which have outlived the cottonwoods and willows, are not so large yet as the patriarchal trees in. old New-England villages, yet time alone is needed to match, in the valley of the Missouri, the elms in the valley of the Connecticut.
I think, with due appreciation of its summer luxuriance of foliage, and the grace and strength of the elm's frame-work in winter, that the moment of greatest charm in the life of a roadside elm comes in the first warm days of late March. The brown buds on the sides of the twigs are swelling and a flush of purple overspreads the tree, while snow still covers the ground. A tremendous "fall of leaves" ensues, for the tiny bud scales that enclose the elm flowers are but leaves in miniature. The elms are in blossom! Each flower of each cluster has a calyx with scalloped edges, and a fringe of four to nine stamens hanging far out and surrounding the central solitary ovary. The color is in the yellow anthers and the dark red calyx lobes.
Speedily, the stamens shrivel and pale green pendants, which are the seeds, cluster upon the twigs. Winged for flight, these ripen and are scattered before the leaves are fairly open, and the growth of the season's shoots begins. Only the pussy willow, the quaking asp, and the earliest maples bloom as early as the elm. How much they have missed, who never saw an elm tree in blossom!
The hubs of the "one-hoss shay" were of "ellum," its interlacing fibres peculiarly fitting this wood for indestructibility. Saddle trees, boat timbers, cooperage, and flooring employ it in quantities. It is also used for flumes and piles, for it resists decay on exposure to water.
The Slippery Elm
U. fulva, Michx.
The slippery elm is also known as the red elm and moose elm, because its wood is red and moose are fond of browsing its young shoots. In regions where moose are rarely seen, it is the small boy who browses and often utterly destroys every specimen of this valuable tree. Under the bark of young shoots a sweet substance is found, which gives the tree its common name. What man lives who in the heydey of youth has not had the spring craze for slippery elm bark, as surely as he had the fever for kite-flying and playing marbles? The trees in every fence row show the wounds of jack-knives; stripping the bark, the boys scrape from its inner surface the thick, fragrant mucilaginous cambium—a delectable substance that allays both hunger and thirst. Fortunately the bark of the limbs supplies the demand; many a veteran tree still suffers the pollarding process, serving one generation of schoolboys after another.
The inner bark, dried and ground and mixed with milk, forms a valuable food for invalids. Poultices of slippery elm bark relieve throat and chest ailments. Fevers and acute inflammatory disorders are treated with the same bark, which has passed from the list of mere home remedies to an established place on the apothecary's shelf.
How shall we tell a slippery elm tree from the American elm? By its leaf in summer. The roughness of the foliage is one of its striking characteristics. Crumple a leaf, and its surfaces grate harshly, for they are covered with stiff, tubercular hairs. The leaves are larger, often reaching seven inches in length. There is a reddish or tawny pubescence on all young shoots, and especially on the bud scales in winter. The tree itself, in winter or summer, is much more coarse than its cousin. It is also unsymmetrical in habit, each limb striking out for itself. Very often one meets a tree quite as one-sided in form as its leaf, and this without any apparent reason. But given a chance to grow without mutilation, the slippery elm attains a height of seventy feet, forming a broad, open head, in comparatively few years. It is well worth planting for its lumber and for shade.
The Rock Elm
U. Thomasi, Sarg.
The rock elm or cork elm chooses dry, gravelly upland and low heavy clay soil, on rocky slopes and river cliffs, from Ontario and New Hampshire westward through northern New York, southern Michigan to Nebraska and Missouri. It is more abundant and of largest size in Ontario and in the southern peninsula of Michigan.
Its leaf is small, thick, and firm, dark green, and turns to brilliant yellow in the autumn. Its flowers and fruits are borne in racemes. At any season, one knows this cork elm by the shaggy bark on its stout limbs that make the tree resemble a bur oak. "Rock elm" and "hickory elm" are names that refer to the hardness of the wood. The wheelwright counts it the best of all elms. Compact, with :interlacing fibres, there are spring, strength, and toughness in this wood which adapt it for bridge timbers, heavy agricultural implements, wheel stocks, sills, and axe-handles. The name "cork elm" refers to the corky bark which runs out in winged ridges, even to the twigs.
The Winged Elm
U. alata, Michx.
The winged elm, or wahoo, is dainty and small, its leaves and the two thin corky blades that arise on each twig befitting the smallest elm tree in the family. Despite its corky wings, it has none of the ruggedness of the cork elm, but is a pretty round-headed tree. It is distributed from Virginia to Florida and west to Illinois and Texas. "Mountain elm" and "small-leaved elm" are local names. "Wahoo" is local also, belonging chiefly to the South. Even the little seed of this tree is long and slender, its wing prolonged into two incurving hooks.
The English Elm
U. campestris, Linn.
The English elm is often seen in the Eastern states, planted with the American elm in parks and streets, where the two species contrast strikingly. The English tree looks stocky, the American airily graceful. One stands heavily upon its heels, the other on tiptoe. One has a compact, pyramidal or oblong head, the other a loose open one. In October the superb English elms on Boston Common are still bright green, while their American cousins have passed into "the sere and yellow leaf."
The Scotch Elm
U. montana, Linn.
The Scotch or wych elm is planted freely in parks and private grounds. It is a medium-sized tree of rather more strict habit of growth than the American elm. Before the leaves open the tree often looks bright green from a distance. This appearance is due to the winged seeds which are exceptionally large and crowd the twig in great rosettes.
One horticultural variety of this species is the weeping form known as the Camperdown elm, which arches its limbs downward on all sides, forming when full-grown a natural arbor. One often sees this tree planted on lawns of limited extent, and so near the street as to render utterly absurd its invitation to privacy. To serve that reasonable and delightful end, the tree should be planted in a retired corner of one's grounds, where an afternoon siesta may be enjoyed undisturbed.