ARBOR Thuja, a genus of plants of the natural order conifera, allied to the cypress, and consisting of evergreen trees and shrubs with compressed or flattened branchlets—small, scale-like, imbricated leaves—and moncecious flowers, which have 4-celled anthers, and the scales of the strobiles (or cone's) with two upright ovules.—The common A. V. (T. occidentalis) is a native of North America, especially between lat. 45' and lat. 49', but has long been well known in Europe. It is a tree of 40 to 50 ft. high ; its branches are horizontally expanded, and the strobiles (cones) small and ()borate. The young leafy twigs have a balsamic smell, and both they and the wood were formerly in great repute as a medicine; the oil obtained by distillation from the twigs, which has a pungent and camphor-like taste, has been recently recommended as a vermifuge. The wood of the stem is reddish, soft, and very light, but compact, tough, and durable, bearing exposure to the weather remarkably well. The tree is very com mon in Britain, but planted chiefly as an ornamental tree, and seldom attaining so great a size as in its native country. It delights in cool, moist situations.—The CHINESE A. V. (7. oricntalis), a native of China and Japan, which is immediately distinguishable from the former species by its upright branches and larger, almost 'globose and rough strobiles, is also in Britain, and upon the continent of Europe, a common ornament of pleasure-grounds; but. it does not attain so great a size as the preceding, and is more
sensible of the cold of severe winters. The balsamic smell is very agreeable. The tree yields a resin, having a pleasant odor, to which high medicinal virtues were formerly ascribed; hence the remarkable name arbor vita (Latin, signifying tree of life), given to this species, and extended to the genus. Other species are known, but they are less important than these. In its native country, this species also attains the size of a con siderable tree.—There are several other species of thuja, some of which seem well suited to the open air in the climate of Britain, and others require the protection of green houses. Amongst the former are T. plicata, from Nootka sound; and T. dolabrata, a native of Japan. a tree of great height and thickness, and which will not improbably prove the most important of the whole genus.—A tree. common in North America, and there known by the name of WHITE CEDAR, is sometimes included in the genus thuja, under the name of T. splueroidea. but is more generally ranked in the genus cc presses as a thyoides. See CYPRESS. The timber is highly esteemed, and an infusion of the scrapings is sometimes used as a stomachic.—Closely allied to the genus thuja is callitris.
See SANDARAC]."