Bidens biternata, an
annual herb that grows to 0.3-1.5m in height, occurs in somewhat
damp locations like roadsides or dry riverbeds, with stems with four
ridges and curly hairs. Leaves on the upper parts are alternate,
9-15cm in length, of mono- or bi-pinnate compound leaf; the leaflets
are oval with pointed tips and fine serrations on the margins.
Branch tips on the upper parts set 0.7-1cm-in-in diameter yellow
flower heads, and involucral bracts, 3-6.5cm long, are linear with
tips sharply pointed. Bloom time: September-October.