Ash is a wood which is frequently employed for interior finishing in public buildings, such as school houses, churches, and so forth, and also in the cheaper classes of dwelling houses. It is one of the cheapest of hard woods, and is used when it is desired to have a hard-wood finish and when the more expensive kinds of hard wood, such as oak, can not be afforded. The wood is somewhat like oak in texture and appearance, the difference being that ash is coarser, and the pith rays do not show. It is strong, straight grained, and tough, comparatively easy to work, elastic, and fairly durable. It shrinks moderately, seasons with little injury, and will take a good polish. The trees do not grow together in forests, but are scattered. They grow rapidly, and attain only medium height. Of the six different species found in the United States, only two, the "white ash," and the "black ash," are used extensively in building work. The first is most common in the basin of the Ohio River, but is also found in the North from Maine to Minnesota, and in the South, in Texas. The black ash is found from Maine to Minnesota, and southward to Virginia and Arkansas. There is very little difference between the two species. The black ash is also known as the "hoop ash," and the "ground ash."