Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
Bidens L. -- Beggarticks
Weedy annuals varying greatly in size and degree of branching. Leaves
simple or ternately to pinnately compound, opposite, obscurely to coarsely serrate,
sessile or petiolate. Heads discoid or radiate, the ray florets, when
present, rather few, sterile or rarely pistillate, the ligules yellow; involucral
bracts biseriate and dimorphic, the outer row usually foliaceous and spreading,
the inner row short and erect, membranous, striate; receptacle flat to
convex, chaffy, the chaffy bracts narrow, membranous, conspicuously few-nerved;
disk florets perfect, numerous or sometimes few, the corollas yellow;
style branches flattened, bearded above. Achenes flattened parallel to
the involucral bracts, narrowed at the base and widening upward, more or less
truncate at the apex, with a pappus of 2-4 retrorsely barbed awns which
persist atop the achene, the achene body also barbed or stiffly appressed-hairy
at least on the angles, the achenes commonly functioning as stick-tights in
animal fur and clothing by means of the barbs.
Fassett, N. C. 1925. A key to the northeastern species of Bidens. Rhodora
Sherff, E. E. 1937. The genus Bidens. Publ. Field Mus. Nat. Hist., Bot.
Weedon, R. R. 1973. Taxonomy and distribution of the genus Bidens
(Compositae) in the north-central Plains States. Unpubl. Ph.D. thesis, Univ.
||Leaves simple and toothed, some rarely incised or
||Leaves all ternately or pinnately compound.
||Achene margins barbed downward for their entire
||Achene margins (and often the faces) barbed upward
at least toward the base.
||Achenes with 4 awns; heads nodding after flowering
(except on depauperate specimens).
||Achenes with 3 awns; heads erect.
||Rays well-developed and conspicuous, 1 cm or more
||Rays absent or poorly developed and inconspicuous,
less than 5 mm long.
||Leaves pinnate-pinnatifid to bipinnate, the leaflets
lobed; achenes with (2)3-4 awns.
||Leaves pinnate or 3-foliate, the leaflets serrate;
achenes with 2 awns.
||Outer involucral bracts 5-10, typically 8; achenes
dark brown to blackish.
||Outer involucral bracts 10-16 or more, typically
13; achenes olivaceous to yellowish, or occasionally brown.
49. Asteraceae, the Aster Family
3. Bidens L. -- Beggarticks
- 1. Bidens bipinnata L. -- Spanish
- 2. Bidens cernua L. -- Nodding beggarticks
- 3. Bidens comosa (A. Gray) Wieg.
- 4. Bidens connata Muhl. ex Willd.
- 5. Bidens coronata (L.) Britt. --
- 6. Bidens frondosa L.
- 7. Bidens vulgata Greene
Return to Family -- Asteraceae - The Aster Family
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