Japanese name: コバノセンダングサ（小葉栴檀草） Scientific name:Bidens bipinnata
[Overview]
An annual 30–90 cm tall, found along roadsides and in vacant lots.
The stem is erect, branched, ridged, and almost hairless.
The leaves are 2-pinnately compound, opposite on the lower part of the stem and alternate on the upper part; the lower leaves are sometimes 3-pinnately cleft to the middle.
Both sides of the leaves are slightly hairy, and the terminal leaflet is narrow, long-pointed at the tip, and has 1–2 pairs of teeth.
Flower heads are borne at the branch tips on the upper part of the stem, each with 1–3 yellow ray florets.
The outer involucral bracts are broadly linear, 5–7 in number.
The fruit is an achene with 3–4 awns (spines).
The awns have small downward-pointing barbs.
[History]
It naturalized in Japan long ago, and a Japanese name was given in 1925 and reported based on a specimen collected in Komoro, Nagano.
