Japanese name: コシロノセンダングサ（小白栴檀草） Scientific name:Bidens pilosa var. minor
[Overview]
An annual 50–110 cm tall, found along roadsides and in vacant lots.
The stem is erect, branched, 4–6-ridged, and covered with short hairs.
The leaves are pinnately compound, 10–14 cm long, opposite on the lower part of the stem and alternate on the upper part, and consist of 3–5 leaflets.
Some leaves on the upper part of the stem are not pinnately compound but are 3-lobed or simple and lanceolate.
The leaf margins are serrated.
Flower heads are borne at the branch tips on the upper part of the stem, each with 4–7 white ray florets.
The outer involucral bracts are spoon-shaped with widened tips, 7–8 in number.
The fruit is an achene with 2–4 awns (spines).
The awns have small downward-pointing barbs.
[History]
It arrived in Japan in the Edo period and has naturalized from the Kanto region westward.
