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Northeast Wetland Flora

Field Office Guide to Plant Species

Awnless Beggar-ticks
Bidens polylepis Blake

JPG -- Species Photo JPG -- Distribution Map

Family: Composite (Compositae)
Flowering: August-October
Field Marks: The distinguishing features of this species are its pinnately compound leaves, conspicuous ray flowers, 10 or more bracts subtending each flowering head, and its usually awnless achenes.
Habitat: Wet ground, roadside ditches.
Habit: Annual or biennial herb with fibrous roots.
Stems: Upright, much branched, usually hairy, up to 3 feet tall.
Leaves: Opposite, pinnately compound, the leaflets linear to lanceolate, coarsely toothed or shallowly lobed, smooth, up to 3 inches long.
Flowers: Many crowded in heads, with numerous heads on slender, rough stalks up to 4 inches long, each head with about 8 bright yellow rays up to 1 inch long and numerous tubular disk flowers, each head subtended by 10 or more leafy bracts.
Sepals: 0.
Petals: Some united to form flat rays, others united to form tubular disk flowers.
Stamens: 5.
Pistils: Ovary inferior, sparsely hairy.
Fruits: Achenes crowded into heads, each achene flat, sparsely hairy on the faces, with stiff hairs on the edges, up to 1/4 inch long, usually with a pair of 2 short awns at the tip, or the awns absent.
Notes: This family is Asteraceae according to Gleason and Cronquist. This species is expanding its range from the midwest eastward.

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Page Last Modified: Thursday, 03-Aug-2006 11:39:25 EDT
Sioux Falls, SD [sdww55]