The article presents the results of an anatomical study of vegetative shoots of North American Acer negundo L. found in Khabarovsk. It was found that annuals remained covered with epidermis during the winter and are not replaced by periderm. Formation of periderm is observed in shoots starting from the second year of vegetation. The formation of phellogen is noted in the subepidermal layer. Periderm appears in separate fragments, and not as a continuous ring around the circumference of the shoot. It was concluded that this species lacks complete maturation of the integumentary tissues of annual shoots. Presumably, this feature is constitutional and taxon-specific.
Tsyrenova et al. (Sun,) studied this question.