Bidens frondosa Linnaeus
The words or terms in red
(actually dark orange) in the text are defined in a
Bidens frondosa is a herbaceous plant
native to North America where it is widely
distributed. In the U.S., is it one of the most widely distributed and annoying
weeds, thanks to its achenes
which are readily carried from place to place in
the hair or fur of animals, especially sheep.
The achenes also stick readily to the clothes of passersby
becoming a real nuisance in early autumn.
The plant belongs to the
In Latin, bis means twice and dens means tooth so
that bidens means two-toothed; hence the
genus name refers to the
achenes of the plant,
even if these seeds have, at times, three or four bristles.
In Latin, frondosus means covered with leaves
and is not that much of a qualifying epithet
since Bidens frondosa has no more and no less leaves than
than other Bidens species.
Some of the vernacular names of
Bidens frondosa are:
Devils Beggarticks, Common Bur-Marigold, Bur Marigold, Devil's Bootjack,
Devil's Pitchfork, Devil's Beggartick, Devils Beggartick, Sticktights,
Tickseed Sunflower, Largeleaf Beggarticks, Old Ladies' Clothespins,
Pitchfork Weed and Sticktight.
Some of its French vernacular names are:
Bidens feuillu, Bident feuillé and Bident à fruits noirs.
Bidens frondosa has also been known as:
- Bidens frondosa L. var. anomala Porter ex Fern.
- Bidens frondosa L. var. caudata Sherff
- Bidens frondosa L. var. pallida Wieg.
- Bidens frondosa L. var. stenodonta Fern. & St. John
Bidens are well known for taxonomic
taxonomic difficulty, the species having plastic
Bidens frondosa is identified by :
Bidens frondosa resembles Bidens pilosa with generally similar
characters, but the achenes of the later are longer, more slender
- its flower heads
without ray florets
divided leaf segments;
- its 5 to 8 leafy phyllaries.
Bidens frondosa also resembles Bidens cernua
(when the later has no ray florets)
except that the leaves of the former are long-stalked and divided
into 3 or 5 sharply toothed leaflets, and the achenes have two
Bidens frondosa is an erect annual
with a taproot that branches frequently.
- Stout, erect, herbaceous, branching.
- Measuring about 3 feet but up to 5 or 6 feet.
- Four-angled with the angles rounded.
- Essentially glabrous but with a few
antrorse hairs in upper portions.
- Often purple in bright sunlight, otherwise green.
- With a petiole
between 10 to 40 mm long.
- Most often trifoliolate,
at times with 5 folioles,
with sometimes a few simple
leaves near the flowerheads.
- Lateral leaflets with short
petiolules a few millimeters long.
- Terminal leaflet petiolule longer, up to one inch long.
- Terminal leaflet larger than the lateral leaflets.
- With serrate margins;
- usually puberulent above,
- Light green below, deep dull green above.
- Often turn dark red during the fall.
- About one inch across.
- On 10 to 40 mm peduncles.
- Without ray flowers.
- With five lobes yellowish,
golden yellow disk flowers.
- With an outer serie of 5 to 8, up to one inch long
green phyllaries with
occasionally with a few serrate.
- With an inner serie of yellowish-green phyllaries,
up to 7 mm long and broad.
- Blooming from the middle of August to September in my area,
25 km north of Montréal.
- Barbed achenes about 5 mm long,
becoming slightly wider toward the
- With two awns about 3 mm long.
Bidens frondosa is found on moist areas of black soil prairies,
in moist meadows near woodlands or rivers, in floodplain woodlands and
young flatwoods, in thickets, marshes, swamps, seeps, and borders of ponds or
lakes, in low-lying areas along railroads and roadsides, in both cultivated and
abandoned fields, in drainage ditches and miscellaneous waste areas. This plant
likes disturbed areas.
Bidens frondosa can be found in most of the USA States and in all
Canadian provinces; it is not found (for the time being) in Montana, and
Alaska, nor in the Canadian territories.
In Europe, it is established in Sicily, in peninsular
Italy, and in Germany. The map shows the USA States and Canadian provinces
where Bidens frondosa can be found.
Bidens frondosa is eaten by muskrats (Ondatra zibethicus)
and the achenes are eaten by ducks.
Infusions and tinctures of Bidens frondosa are rated as outstanding
herbal therapies for irritation, inflammation, pain, and bleeding of the
urinary tract mucosa and are used for benign prostatic hypertrophy and
increasing excretion of uric acid, decreasing the risk of
as well as other medical uses.
The photos of the gallery were taken either with one of the following:
The title in the window shows the date when the picture was taken,
i.e. jan_30_06... would mean that the photo was taken on the 30th of
January, the 06 is for the 6th picture taken that day.
- Minolta DiMAGE 7.
- Canon PowerShot A530
- Canon Xt Rebel, usually with the EF-S60mm f/2.8 Macro USM objective.
- EPSON Perfection 1650 (scanner).
The month, day and picture number might be followed by a letter:
- c for the Canon Xt Rebel.
- a for the Canon A530.
- m for the Minolta DiMAGE 7.
- s for the EPSON scanner.
Click on the thumbnails to get larger view.
The original photos are usually in TIFF format,
the photos shown are generally in JPEG format,
usually of dimensions one half (surface one quarter)
for loading time reduction.
The leaves were scanned at 300 dpi,
and the dimensions of the resulting picture divided by 2 (area divided by 4);
this allows to measure the dimensions of the leaves.