Betula cordifolia that "Betula cordifolia" and "Betula papyrifera" hybridise, however this is unlikely given the more recent evidence of different chromosome numbers. The most conclusive method of identification is from chromosome analysis. Betula cordifolia Betula cordifolia (mountain paper birch, also known as mountain white birch or eastern paper birch) is a birch species native to Eastern Canada and the Northeastern United States. Until recently it was considered a variety of "Betula papyrifera" (paper birch), with which it shares many characteristics, and it was classified as "B. papyrifera" var." cordifolia" (Regel) Fern. "Betula cordifolia" is a deciduous tree that reaches heights of about
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