ALDER, aVdilr (Lat. ohms). A genus of plants of the natural order Betulacere. (See Bmen.) The geniis consists of trees and shrubs, natives of cold and temperate climates: the flow ers in terminal, imbricated eatkins, which ap pear before the leaves in some species, though in other species leaves and flowers appear simul taneously. In Abuts maritima the flowers ap pear in the autumn and the fruits ripen in the following season. The common or black al der (.1Inus ylutinoRa) is a native of Great Britain and of the northern parts of Asia and America. It has roundish, wedge-shaped, obtuse leaves, loped at the margin and serrated. The bark, except in very young trees, is nearly black. It succeeds best in moist. soils, and helps to secure swampy river-banks against tire effects of floods. It attains a height of 30 to 60 feet. The wood is of an orange-yellow color. It is not very good for fuel, but affords one of the best kinds of charcoal for the manufacture of gunpowder, upon which account it is often grown as coppice-wood. Great numbers of small alder trees are used in Scotland for making staves for herring barrels. The wood is particularly valu able on account of its property of remaining for a long time under water without decay, and is therefore used for the piles of bridges, for pumps, sluices, pipes, cogs of mill-wheels, and similar purposes. The bark is used for tanning and for dyeing. It produces a yellow or red color, or. with copperas, a black color. The leaves and female catkins are employed in the same way by the tanners and dyers of some countries. The bark is bitter and astringent. The individual tree, viewed by itself. may be re gardcd as somewhat stiff and formal in appear ance, but in groups or clusters it is ornamental.
The northern limit of the common alder is the Swedish shire of the Gulf of Bothnia, in the south of Angermannland, where it is called the sea alder, because it is only in the lowest grounds, near the sea, that it occurs. The gray or white alder (dlnus lacuna), a native of many parts of continental Europe, especi ally of the Alps. and also of North America and of Kanitchatka. but not of Great Britain, differs from the common alder in having acute leaves, downy beneath, and not glutinous. It attains a rather greater height, but in very cold climates and unfavorable situations appears as a shrub. It occurs on the Alps at an elevation above that to which the common alder extends, and becomes abundant also where that species disappears in the northern part of the Scandinavian peninsula. The wood is white, line-grained, and compact, but readily rots under water. The bark is used in dyeing. Alnus cordifolia is a large and handsome tree, with cordate acuminate leaves, a native of the south of Italy, but found to be quite hardy in England. Some of the American species are mere shrubs. The bark of the smooth alder (Alnus scrrulatu), found from south New England to Wisconsin, Kentucky, and Florida. is used in dyeing. The green or mountain alder (A Inns viridis) ranges from north New England to the shores of Lake Superior, and northward and southward to North Carolina. Alnus oregona is a handsome species of the northern Pacific coast region. In the mountain regions of Alaska and elsewhere alders are the first arboreseent growth to succeed coni fers swept away by avalanches or other means. Several species are natives of the Hima layas.