This European tree is widely planted across North America, especially fastigiate cultivars, but there are almost no reports of naturalization (FNA 9, K). With leaves along, betulus is easily confused with caroliniana, and there can be confusion for supposedly native plantings. More definitive comparison is needed, but betulus may be distinguished as folllows (FNA 3; Missouri Botanical Garden 2023; Colllege of Dupage 2023.): tree up to 12-25 m (versus 12 m); winter buds appressed to stem, almost wrapping (versus divergent); leaf blade base cordate to rounded (versus subcordate to truncate); lower leaf surface with ca. 2-3 mm long appressed hairs on main veins (versus with sparse ca. 1-2 mm appressed or spreading hairs on main veins); upper surface with scattered long hairs (versus glabrous or with scattered short hairs); female catkins ca. 5-8 cm (versus 1-2.5 cm).