Hieracium aurantiacum Linnaeus
The words or terms in red
(actually dark orange) in the text are defined in a
Hieracium aurantiacum is an introduced
and naturalized perennial
plant with shallow, fibrous roots, stolons,
and well-developed basal rosettes.
It is native to alpine area of central and
southern Europe, where it is protected in several regions.
The plant belongs to the
The genus name is said to come form the Greek
ιεραξ, the falcon,
since the Roman naturalist Gaius Plinius Secundas (Pliny the Elder,
AD 23 - August 24, AD 79) believed that the feathery Accipiters (a group
of birds of prey in the family Accipitridae, the hawks family notably)
fed on plants of this genus to strengthen their eyesight and thus,
Hieracium, as named by Pliny the Elder in his Naturalis Historia
(34, 114) became the genus name, and by extension the Greek and Latin name of
many species of the Hieracium genus, many of these species with the
Hawkweed vernacular name.
In Latin, the adjective aurantiacus means orange-colored, the
epithet obviously referring to the color of
the flower heads.
Some of the vernacular names of
Hieracium aurantiacum are
Devil's Paintbrush, Orange Hawkweed, Red Devil, Grim-the-collier,
Fox and Cubs, Red Daisy and King-devil.
Two French common names are Épervière orangée and
Hieracium aurantiacum has also been known as:
- Pilosella aurantiaca (L.) F. W. Schultz & Sch. Bip.
- Pilosella aurantiaca (L.) F. W. Schultz & Sch. Bip. subsp.
brunneocroceum (Pugsley) P. D. Sell & C. West
- Hieracium aurantiacum L. subsp. carpathicola
Nägeli & Peter
- Hieracium brunneocroceum Pugsley
- Hieracium scandicum (Nägeli & Peter) Omang
Hieracium aurantiacum is easy to identify with its orange flower heads,
with square-edged notched ray florets,
the flower heads clustered at the top of stems covered in stiff black hairs.
The distinguishing features of non-flowering plants include the presence of
stolons and the numerous short black hairs on the stems.
- Erect, usually solitary.
- Covered with short dark-colored hairs.
- Exuding a milky latex
when cut or broken.
- Reaching up to 12 inches.
- With up to more than 20 flowerheads near the top.
spatulate to narrowly
- Almost exclusively basal, with 1 or 2 smaller ones on the stem.
- Up to to 5 inches long.
- Covered with soft white hairs.
- Entire to wavy-toothed.
- Darker on the upper surface than on the lower surface.
- In a flat-topped compact
- About one inch in diameter.
- Without disk florets.
- The ray florets dark orange-red on
the edges, orange clear in the center, notched in the upper margin.
- Blooming from the end of June to the middle of September in my area,
25 km north of Montréal.
- Oblong achenes.
- Purplish black, several-ribbed.
- With a white to brownish pappus
about 4mm long.
- Between 1/16 to 1/8 of an inch long.
- Between 50 and 600 seeds per plant.
Hieracium aurantiacum is usually found in
mesic to submesic sites; it prefers well-
drained soils, growing in permanent meadows, grasslands, rangelands, and
pastures, and thrives in nutrient-poor, uncultivated, or disturbed soils.
As shown on the map, Hieracium aurantiacum has already  invaded
all the Canadian provinces and most states of the USA.
Hieracium aurantiacum was introduced to North America for use as an
herbal remedy and ornamental before 1818. Distribution of this weed has likely
been assisted by flower enthusiasts due to its beauty.
It is native to the alpine and
hillside meadows of Europe and has now established across Eurasia, as well as
from coast to coast in North America.
In Québec, Hieracium aurantiacum is in the list of noxious weeds when
they grow in cultivated lands and pastureland.
Hieracium aurantiacum forms a dense mat of plants in which no other
species can grow, thereby lowering species diversity and reducing the forage
value of grasslands for grazing animals. It is a successful
allelopathic competitor that crowds
out native, pasture, and range species. It
with native and exotic Hieracium. It likely reduces soil
moisture and nutrient availability. It can invade undisturbed sites and is
considered one of the worst nuisance species in agricultural and natural areas.
Hieracium aurantiacum have an advantageous reproductive
strategy relative to their native counterparts in that they are able to
reproduce sexually as well as asexually via vegetative propagation (by
stolons, rhizomes, and root buds) and
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,
and the dimensions of the resulting picture divided by 2 (area divided by 4);
this allows to measure the dimensions of the leaves.