Nodding Beggarticks, Nodding Beggar Ticks, Bur Marigold: Bidens cernua (Synonyms: Bidens cernua var. cernua, Bidens cernua var. elliptica, Bidens cernua var. minima)

Nodding beggar ticks observed in the wetlands at Grizzly Creek Campground, Jackson County Parks, Howard Prairie Lake......July 22, 2021.

Nodding beggar ticks is a somewhat weedy annual with erect to ascending stems from 10-100 cm high. The stems are often branched with either a smooth or slightly rough herbage. The leaves are opposite and are slightly reduced in size upwards along the stem. Individual leaves are simple (as opposed to compound ternate in Bidens frondosa) with a lance-linear to lance-ovate shape (as seen at right) and subentire to coarsely serrate margin. The leaves range from 4-20 cm long and 5-45 mm wide.

The flower heads consist of both disk and ray flowers found at the ends of the main stems as well as on stems originating in the upper leaf axils. The yellowish rays typically number 6-8 although they may occasionally be missing. Individual rays measure to 1.5 cm long and from 1.2-2.5 cm wide. The numerous disk flowers are yellow to brownish in color with yellow stamens. The disk ranges from 12-25 mm wide. The flower heads commonly nod with age, hence the name "nodding" beggar ticks.

The involucre consist of 2 rows of dissimilar bracts. The outer row consists of 5-8 narrow, spreading or reflexed bracts while the inner row consists of wide, striped bracts. The fruits are wedge-shaped achenes with 4 long bristles covered with many tiny, reflexed barbs. The achenes range from 5-8 mm long.

Common beggar ticks Bidens frondosa: The leaves of common beggar ticks typically have petioles and are compound pinnate with 3-5 leaflets. The terminal leaflet is often slenderly petiolate. The flower heads lack ray flowers.

Nodding beggar ticks are found in low wet places such as found in ditches, vernal ponds, and the margins of rivers and streams.

Nodding beggar ticks is a widespread species of the northern hemisphere which was evidently introduced to the west coast from the east coast of the United States.

Nodding beggar ticks along the shoreline at the old mill pond along the Glenwood-Goldendale Highway, several miles east of Glenwood, Washington..........September 4, 2013.

Nodding beggar ticks slightly past bloom as seen in wetlands along the Willard Springs Trail at Conboy Lake National Wildlife Refuge............September 30, 2006. As the flower heads finish their bloom period, the heads begin to nod more noticeably. Note also the serrated leaf margins of the narrow blades, which have no petiole.

The photo above shows the typical habitat of nodding beggar ticks, moist riparian areas at the edge of ponds, streams and canals. Photographed at the fishing area along Lakeside Rd in Conboy Lake NWR...........September 8, 2007.