Japanese name: オナモミ（雄生揉、葈耳） Scientific name:Xanthium strumarium subsp. sibiricum
[Overview]
An annual 0.2–1 m tall, considered a prehistoric naturalized plant.
The stem is pale green and rough with short hairs.
The leaves are alternate, ovate-triangular, 6–15 cm long, and 3–5-lobed.
Both surfaces of the leaves are rough with stiff hairs.
The leaf margins have irregular teeth.
The petiole is 3.5–10 cm long.
The flowers are either male or female; the male flowers are yellowish white and borne in short conical clusters in the leaf axils, while the female flowers are pale green and borne in the leaf axils below the male inflorescence.
The fruit is ovate to elliptic with two horns at the tip, about 0.9–1.4 cm long including the horns and 0.6–0.8 cm wide, and turns yellowish green to grayish brown when ripe.
The fruit surface is densely hairy and dull, with sparse prickles 0.1–0.2 cm long that are hooked at the tip.
