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
Crataegus Crataegus Crataegus (), commonly called hawthorn, quickthorn, thornapple, May-tree, whitethorn, or hawberry, is a large genus of shrubs and trees in the family Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name "hawthorn" was originally applied to the species native to northern Europe, especially the common hawthorn "C. monogyna", and the unmodified name is often so used in Britain and Ireland. The name is now also applied to the entire genus and to the related Asian genus "Rhaphiolepis". The Latin name "Crataegus" is from the Greek "kratos" "strength" and "akis" "sharp", referring