Nat. Ord. (Natural Order) Conifer�. Lin. Syst. (Linnean System) Mon�cia, Monadelphia. The Arbor Vit� (Thuja occidentalis), sometimes also called Flat Cedar, or White Cedar, is distinguished from most evergreens by its flat foliage, composed of a great number of scales closely imbricated, or overlaying each other, which give the whole a compressed appearance. The seeds are borne in a small cone, usually not more than half an inch in length.