Japanese name: ナンバンアカバナアズキ（南蛮赤花小豆） Scientific name:Macroptilium lathyroides
[Overview]
An annual 1 m tall, found along roadsides and on waste ground.
It often becomes a biennial or a short-lived perennial.
The stem is erect, woody at the base, and branches.
In poorly lit places it may become vine-like.
The leaves are alternate and trifoliate; the leaflets are narrowly ovate to lanceolate, 3–8 cm long and 1–3.5 cm wide, with soft hairs on the underside.
The leaf margins are entire.
The stipules are narrowly ovate, 0.5–1 cm long.
If the temperature is high enough, it flowers almost all year round.
Racemes 15–25 cm long bear sparse flowers.
The flowers are pea-shaped, about 1.5 cm across, deep crimson to deep reddish purple tinged with brown; the wing petals are larger than the standard, the keel petals enclosing the stamens and pistil make one full turn, and the style curves inward by 90 degrees.
The fruit is a linear pod 5.5–12 cm long and about 0.3 cm wide.
[History]
It has been confirmed as naturalized in Okinawa.
