Flower:

 1 to 3 stalked flower heads at the ends of branching stems. Flower heads are broad, up to 1 inch across, made up of tiny light yellow disk flowers with 4 or 5 lobes. 3 to several short yellow ray flowers (petals) irregularly spaced around the disk are usually present, but rays may be absent altogether. Inner bracts are inconspicuous yellow, triangular blades tucked around the perimeter of the center disk.

The head is surrounded by 10 to 20 leafy outer bracts that are up to 2 inches long, linear to narrowly spatula shaped, coarse textured and often rippling with dense stiff hairs, often curled or with rolled edges.

Leaves and stems:

Leaves are compound in groups of 3 or 5, oppositely attached, though a few simple leaves may be alternately attached near the flowers. Leaflets are 2 to 4 inches long, ½ to 1 inch wide, on a sturdy stalk, with the end leaflet largest. Leaflets are generally lance shaped, tapered to a blunt rounded tip, narrowing more abruptly at the base, with rounded teeth around the edges, densely hairy along the edges and undersides. Stems are stout and erect, many branched, green to reddish, often smooth at the base becoming densely hairy above.

Fruit:

Fruit is a flat, olive green to brown seed ¼ to 1/3 inch long with a mostly smooth surface and 2 barbed awns that are erect or somewhat spreading.

Notes:

There are several species of Bidens with similar flowers, but they are not so difficult to tell apart once you know the secret. Devil's Beggarticks (Bidens frondosa) also has leaves compound in 3s or 5s, but only 4 to 9 leafy bracts, a smaller flower head, and rarely grows taller than 30 inches. Three-lobed Beggarticks (Bidens tripartita) also has a broad yellow flower head, but has mostly simple leaves, not compound, and broader leafy bracts that are less hairy. Purple-stem Beggarticks (Bidens connata) also has mostly simple leaves, a smaller flower head that is more orange than yellow, few leafy bracts, and 4-angled seeds that usually have 2 to 4 awns.