Betula papyrifera the genus "Betula". Several varieties are recognized "Betula papyrifera" is mostly confined to Canada and the far northern United States. It is found in interior (var. "humilus") and south-central (var. "kenaica") Alaska and in all provinces and territories of Canada, except Nunavut, as well as the far northern continental United States. Isolated patches are found as far south as the Hudson Valley of New York and Pennsylvania, as well as Washington. High elevation stands are also in mountains to North Carolina, New Mexico, and Colorado. The most southerly stand in the Western United States is located in Long Canyon in
Fokienia Tuyên Quang, Yên Bái and Vĩnh Phú), west central Vietnam (provinces of Đắk Lắk, Gia Lai, Lâm Đồng), and west to northern Laos. The name derives from the old Romanised name of Fujian province, China, from where the first specimen was introduced to Europe, collected by Captain Hodgins in 1908. "Fokienia" is an evergreen tree, 25–30 m tall. It has greyish-brownish bark that peels off when the tree is young. On older trees, the bark presents longitudinal fissures and becomes aromatic. The leaves are arranged in flattened branchlet systems, with the branchlets in one plane. The leaves on adult trees