As with most of our Western streams the principal arboreal growths along the banks of the Missouri are the willow and cottonwood. The willow matures very rapidly, and well-grown forests are constantly met with in places where the river flowed but two or three years before. The cottonwood requires more time to mature, but this is afforded by those longer cycles of change in which the river passes back and forth across the bottoms. On many of the islands along the central portion of the river there were formerly extensive growths of cedar. The walnut and other trees abound to a less extent. Every year great numbers of trees that line the river bank are undermined and fall into the stream. They are borne along by the current until they become anchored in the bottom, where they remain with one end sticking up and pointing downstream, sometimes above and sometimes below the surface. These trunks or branches have always been the most formidable dangers to navigation of the river. They are called snags or sawyers, though sometimes, from the ripple or break in the surface of the water, “breaks.” It is, in fact, only by the appearance of these breaks that a submerged snag can be discovered by the pilot; and fortunately, in a rapid current, like that of the Missouri, a snag will cause such a break if it is near enough to the surface to touch the bottom of a boat. These snags were the terror of the pilot, as well they might be. The record of steamboat wrecks on the Missouri, and it is an appalling one, shows that about seventy per cent. were due to this cause. [Sidenote: THE MISSOURI IN WINTER.]