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Published In: Species Plantarum 2: 832. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 8/26/2009)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native

 

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5. Bidens cernua L. (sticktight, nodding bur marigold)

B. cernua var. elliptica Wiegand

B. cernua var. integra Wiegand

Pl. 273 a, b; Map 1153

Plants annual, terrestrial or occasionally emergent aquatics, sometimes with taproots. Stems 10–80(–250) cm, erect to loosely ascending, sometimes from a spreading base, occasionally rooting at the lower nodes, glabrous or rarely somewhat roughened with sparse, stiff, ascending hairs. Leaves all more or less similar, sessile, opposite or rarely the lowermost leaves in whorls of 3, the blade 2–20 cm long, oblong-lanceolate to oblanceolate in outline, unlobed, narrowed or tapered at the base, tapered to a sharply pointed tip, the margins sharply and finely to coarsely toothed, rarely nearly entire, also minutely roughened, the surfaces glabrous. Inflorescences of solitary terminal heads or appearing in loose, open clusters, the heads radiate or rarely discoid, usually nodding at fruiting. Involucre with the outer series of 5–9 bracts 6–30(–45) mm long, spreading to more commonly reflexed, mostly leaflike, narrowly lanceolate to oblong-lanceolate or linear, the margins entire but usually minutely roughened, the outer surface glabrous or sparsely short-hairy toward the base; the inner series of 6–9 bracts 4–10 mm long, lanceolate to narrowly ovate or ovate, glabrous. Chaffy bracts narrowly oblong, straw-colored to yellowish-tinged at the tip. Ray florets rarely absent, when present then 6–8, the corolla usually showy, (2–)10–15 mm long, yellow. Disc florets 40–100(–150), the corollas 3–4 mm long, yellow to orangish yellow. Pappus of (2–)4 awns mostly 2–4 mm long, these with downward-pointed barbs, erect at fruiting. Fruits 4–8 mm long, narrowly wedge-shaped, more or less flattened and somewhat 4-angled in cross-section, the angles pale and somewhat thickened or sometimes narrowly winged, the faces sometimes with several faint longitudinal lines, dark brown to purplish black, glabrous or with sparse, short, pustular-based hairs. 2n=24, 48. August–October.

Scattered nearly throughout the state but absent or uncommon in the Unglaciated Plains Division (U.S. [including Alaska], Canada, Europe, Asia). Banks of streams and rivers, margins of ponds and lakes, sloughs, swamps, bottomland forests, and fens; also ditches and railroads.

Steyermark (1963) noted that the species has been used medicinally to treat urinary tract infections. Rare plants with discoid heads have been called f. discoidea (Wimm. & Grab.) Briq. & Cavill. A number of infraspecific taxa have been named, but these appear to represent either ecological variants or minor variants unworthy of formal taxonomic recognition.

 


 

 
 
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