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Bidens frondosa

Asteraceae: Bidens cernua L.
(bur marigold, nodding beggartick)

There are 7 species of the genus Bidens, the beggarticks, in Nova Scotia. All (in N.S.) are annual herbs growing in wet places. Two- or 4-awned fruits (4 in B. cernua) stick to animals or clothing, hence the inclusion of "bur" or "tick" in common names. "Bidens" comes from the Latin for two teeth, referring to the awns. The flowers of Bidens spp. may be discoid or radiate, with yellow rays in the radiate types. Leaves are always opposite. B. cernua has hemispherical (as opposed to bell-shaped) erect to nodding, usually radiate flowers with 6-8 rays, sessile clasping leaves (versus petiolate leaves) and loosely spreading (as opposed to ascending) outer bracts. The specific epithet cernua is from the Latin for stooping, referring to the nodding habit of flowers. The species grows to 2.7 meters (5 feet) height. It occurs throughout N.S. at edges of lakes, ponds, along stream, swamps, wet meadows. B. cernua is disributed throughout most of North America, also occurs in Europe and Asia.
Sources | Selected Web Resources | Line Drawing

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Aug. 31, 2008 Haliax County: Frog Pond (Halifax). Photographer: JackPine.
Bidens cernua, habitat Bidens cernua, habit
Bidens cernua, flower

Nodding flowers.

 Bidens cernua, node

Clasping leaves.
Bidens cernua, leaves

Leaf: lower (left) and upper surfaces.
Bidens cernua, flower, dorsal view

Flower: from above.

 Bidens cernua, flwoer, ventral view

Flower: from below, showing bracts.
Sep 15, 2008 Haliax County: Frog Pond (Halifax). Photographer: JackPine.
Bidens cernua, flowers

Same site as Aug. 31, most flowers are post-bloom.

 Bidens cernua, fruits

Maturing fruits. Bar is 1 cm.
Oct. 22, 2008 Haliax County: Frog Pond (Halifax). Photographer: JackPine.
Bidens cernua, Habitat

Same site as Aug. 31.

 Bidens cernua, Inflorescense
Bidens cernua, Seeds on clothing

Fruits on clothing.

Selected Web Resources