Betula uber Betula uber Betula uber, Virginia round-leaf birch, is a rare species of tree in the birch family. One of the most endangered species of North American trees, it is endemic to Smyth County, in the U.S. state of Virginia. It is part of the temperate broadleaf and mixed forests biome. The tree was first described in 1918 as a variety of "Betula lenta", and elevated to species status in 1945. It hybridizes with "B. lenta" and it has been suggested that it is actually a round-leaved mutant form of "B. lenta". Some authorities prefer to treat it as a variety.
Thuja occidentalis its common names, it is not a true cedar in the genus "Cedrus", nor is it related to the Australian white cedar, "Melia azedarach". Unlike the closely related western red-cedar ("Thuja plicata"), northern white-cedar is only a small or medium-sized tree, growing to a height of tall with a trunk diameter, exceptionally to tall and diameter. The tree is often stunted or prostrate in less favorable locations. The bark is red-brown, furrowed and peels in narrow, longitudinal strips. Northern white-cedar has fan-like branches and scaly leaves. The foliage forms in flat sprays with scale-like leaves long. The seed cones are