Alnus japonica

Japanese alder is a member of the birch or Betulaceae family and is native to Japan. It typically grows up to 25 m tall, favoring streambanks and swamps.

• Leaves are alternate, simple, narrow, pointed, ovate, up to 12 cm long, untypical of most alders. They do not have appreciable fall colour.
• Species is monoecious. Male flowers form clusters of long, pendant catkins. Females are short, erect catkins, maturing into egg-shaped woody (non-fragmenting) seed cones up to 2.5 cm long containing winged seeds.

NOTE:

There are discrepancies regarding the description of Alnus japonica on the websites of various botanical gardens, with some indicating a narrow, pointed leaf and others a more typical oval type of leaf.

On this website, the illustration from 'The Essential Trees of Hokkaido' from Sapporo University Press in Japan was used as confirmation of identification.