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
Eucalyptus rigidula Eucalyptus rigidula Eucalyptus rigidula, commonly known as stiff-leaved mallee, is a mallee that is native to Western Australia. The mallee typically grows to a height of . The bark of the tree is smooth and white-grey brown in colour and peels in ribbony strips at the base. It blooms between December and April producing inflorescences with white flowers. The bark is smooth and powdery with no pith of bark glands. The disjunct, glossy, green or yellow-green adult leaves have a lanceolate to broad lanceolate shaped blade that is basally tapered. The thick concolorous blade is in length and wide. The