Japanese alder
Alnus japonica (Thunb.) Steud.
Alnus japonica, known as Japanese alder, is a species of Alnus in the Betulaceae family. It is native to Japan, Korea, Taiwan, eastern China, and Russia. The species was first described in 1840. It is a deciduous tree with opposite, ovate to triangular-ovate leaves and catkins that appear before the leaves. The plant is wind-pollinated and produces small, triangular, hairy seeds in clusters of 2–4. It is distinguished by its flat petiole base, leaf shape, and the absence of resin in winter buds.
Description
Alnus japonica is a tree species in the Betulaceae family, characterized by its opposite leaves, which are ovate to triangular-ovate in shape. The leaves have a flat petiole base and are typically hairless. Winter buds are non-resinous and contain multiple scales. The plant has separate male and female flowers, with male catkins hanging in clusters and appearing before the leaves. Each male flower has 8–12 stamens. The female flowers develop into small, cup-like structures that mature into woody cones containing 2–4 triangular, hairy seeds. This species is native to Japan, Korea, Taiwan, eastern China, and Russia. It is distinguished from other Populus and Alnus species by its leaf shape, petiole structure, and the number of stamens in the male flowers.
Other common names
Japanese alder
Distribution
Belgium · France · The Netherlands · Great Britain · Global · China North-Central · China Southeast · Japan · Korea · Kuril Is. · Manchuria · Primorye · Sakhalin · Taiwan
Synonyms
Betula japonicaAlnus japonica var. rufinervisAlnus japonica var. koreanaAlnus japonica var. argutaAlnus japonica f. argutaAlnus japonica f. koreanaAlnus japonica var. reginosaAlnus harinokiAlnus japonicaAlnus japonica var. latifoliaAlnus japonica var. minorAlnus japonica var. villosaAlnus maritima var. argutaAlnus maritima var. japonicaAlnus reginosaAlnus borealis var. koreanaAlnus japonica var. genuinaAlnus japonica var. rufaAlnus japonica var. serrataAlnus japonica f. serrata