Leaves are decussately opposite, imparipinnate, with 5-9 leaflets.

Leaflets are broadly lanceolate, acuminate at the apex, acuminate at the base, incumbent serrations, light green and glabrous above, pale green beneath.

Flowers open in May to June with the leaves in axillary on new shoots.

Samarae ripening in October.

This ash is restricted to deep mountain of central Honshu.

The wood is used for sportinggoods, handles of instruments, furnitures.

Distribution ; Honshu (Fukushima to Fukui)