Galinsoga quadriradiata Ruiz & Pavón
The words or terms in red
(actually dark orange) in the text are defined in a
is an introduced and
naturalized invasive weed in North America.
It is one of the most common weeds in the United States and Canada, where it
was introduced from South America.
It is an annual forb that
propagates is only by seeds.
It has many hairy branches that bloom from July to October in my area,
25 km north of Montréal. Its chromosome
number (2n) is 32.
The plant belongs to the
The genus name is after Mariano Martínez de
Galinsoga, 1766-1797, who was court physician and director of the Botanic
Garden in Madrid.
In Latin, quadra or quadrus mean square and the prefix
quad means four, while radiatus means with rays
(as a wheel), so that quadriradiata would mean with four rays
referring to the usually five! ray florets
of the flower heads ?
Some of the vernacular names of
Galinsoga quadriradiata are
Common Quick-weed, Fringed Quickweed, Hairy Galinsoga, Peruvian-daisy,
Quick-weed and Shaggy-soldier.
Its French name is Galinsoga cilié.
Galinsoga quadriradiata has also been known as:
- Adventina ciliata Raf.
- Galinsoga aristulata E. P. Bicknell
- Galinsoga bicolorata H. St. John & D. White
- Galinsoga caracasana (DC.) Sch. Bip.
- Galinsoga ciliata (Raf.) S. F. Blake
- Galinsoga parviflora Cav. var. hispida DC.
- Wilburgia urticifolia Kunth
Galinsoga quadriradiata is easy to identify by its small flower heads
with usually five short and separated white
ray florets and its numerous
yellowish disk florets.
It is however easy to confused it with Galinsoga parviflora
which is paler green, has shorter appressed
hairs while those of Galinsoga quadriradiata are spreading;
furthermore the phyllaries of
Galinsoga parviflora have a rounded
apex instead of an acute one.
- Mostly branched near the base.
- With spreading and dense hairs above.
- Between 1/2 foot to 2 feet long.
- Ovate and
- With a blade broadest at the base.
- With dentate margins.
- With both surfaces bristly hairy.
- Up to 6 cm long and 4 cm wide.
- Several in branched clusters.
- About 3/16" wide.
- Usually with 5, at times 4 to 8, short 3-toothed white (at time pink)
- With many (from 15 to 25) yellowish
- With falling phyllaries with an
- Self-pollinated or
- A black dry achene
about 1.5 mm long.
- With a small white pappus.
Galinsoga quadriradiata is adapted to a warm climate and heavy,
nitrogen-rich and clayey soils.
It is found in gardens, greenhouses, public plantations, cultivated plots,
roadsides, railways and waste places, especially in and near towns and cities.
These habitats are very similar to habitats in its native range,
where it is also a common weed.
Galinsoga quadriradiata is widespread in temperate and subtropic
regions of the Americas and Europe; it native range covers parts of South
and Central America from Mexico to Chile, but due to human activity the species
has been spread far from its original range. The map shows the Canadian
provinces and US states where the plant can be found.
The photos of the gallery were taken either with one of the following:
Minolta DiMAGE 7,
Canon PowerShot A530,
Canon Xt Rebel, usually with the EF-S60mm f/2.8 Macro USM objective,
Fujifilm A 610 and
EPSON Perfection 1650 (scanner).
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.
The month, day and picture number might be followed by a letter which I use
to identify the system used to take the picture.
Click on the thumbnails to get larger view.
The original photos are usually in TIFF format,
the photos shown are generally in JPEG format,
often of dimensions one half (surface one quarter)
for loading time reduction.
The leaves were scanned at 300 dpi;
this allows to measure the dimensions of the leaves.