Hieracium pilosella

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Mouse-ear Hawkweed

Secure

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Asterales
Family:	Asteraceae
Genus:	Pilosella
Species:	P. officinarum

Binomial name

Pilosella officinarum
(L.) F.W.Schultz & Sch.Bip.

Synonyms

Hieracium pilosella L.
Hieracium pseudoincanum t.infr.
Hieracium bauhinii Schult. t.infr.
Pilosella bauhinii (Schult.) Arv.-Touv.
Hieracium adenocladum (Rehmann) Czerep.
Hieracium agathanthum (Rehmann) Czerep.
Hieracium arvorum (Nägeli & Peter) Pugsley
Hieracium callicymum (Rehmann) Üksip
Hieracium cimpiense Prodán
Hieracium cryptomastix (Nägeli & Peter) Freyn
Hieracium cymanthodes (Koslovsky & Zahn) Üksip
Hieracium cymanthum (Nägeli & Peter) Üksip
Hieracium empodistum (Nägeli & Peter) Üksip
Hieracium erythrophylloides (Zahn) Czerep.
Hieracium fastigiatum (Nägeli & Peter) Üksip
Hieracium georgieffianum Zahn
Hieracium hispidissimum (Nägeli & Peter) Üksip
Hieracium ingricum (Nägeli & Peter) Üksip
Hieracium insolens Norrl.
Hieracium limenyense (Zahn) Czerep.
Hieracium macrum (Nägeli & Peter) Üksip
Hieracium melachaetum Tausch
Hieracium mnoocladum (Rehmann) Czerep.
Hieracium obscuribracteum (Nägeli & Peter) Üksip
Hieracium parvistolonum (Nägeli & Peter) Üksip
Hieracium plicatulum Üksip
Hieracium polyanthemum (Nägeli & Peter) Czerep.
Hieracium pseudosparsum (Zahn) Czerep.
Hieracium pseudothaumasium (Zahn) Üksip
Hieracium radiocaule Tausch
Hieracium rojowskii (Rehmann) Üksip
Hieracium sedutrix (Rehmann) Üksip
Hieracium spraguei Pugsley
Hieracium stauropolitanum Üksip
Hieracium thaumasioides (Peter) J. Weiss
Hieracium thaumasium (Peter) J. Weiss
Hieracium varatinense Wo\u0142.
Hieracium viscidulum (Tausch) Üksip
Pilosella adenoclada (Rehmann) Schljakov
Pilosella agathantha (Rehmann) Schljakov
Pilosella arvorum (Nägeli & Peter) Schljakov
Pilosella botrychodes Schljakov
Pilosella callicyma (Rehmann) Schljakov
Pilosella chaunocyma (Rehmann) Schljakov
Pilosella cryptomastix (Nägeli & Peter) Soják
Pilosella cymantha (Nägeli & Peter) Schljakov
Pilosella cymanthodes (Koslovsky & Zahn) Sennikov
Pilosella dobromilensis (Rehmann) Schljakov
Pilosella empodista (Nägeli & Peter) Schljakov
Pilosella erythriophylla (Vuk.) Soják
Pilosella erythrophylloides (Zahn) Schljakov
Pilosella fastigiata (Nägeli & Peter) Schljakov
Pilosella georgieffiana (Zahn) Soják
Pilosella hispidissima (Nägeli & Peter) Schljakov
Pilosella ingrica (Nägeli & Peter) Schljakov
Pilosella insolens (Norrl.) Schljakov
Pilosella limenyensis (Zahn) Schljakov
Pilosella melachaeta (Tausch) Schljakov
Pilosella mnooclada (Rehmann) Schljakov
Pilosella obscuribractea (Nägeli & Peter) Schljakov
Pilosella parvistolona (Nägeli & Peter) Schljakov
Pilosella plicatula (Üksip) Schljakov
Pilosella polyanthema (Nägeli & Peter) Schljakov
Pilosella pseudosparsa (Zahn) Schljakov
Pilosella pseudothaumasia (Zahn) Schljakov
Pilosella rojowskii (Rehmann) Schljakov
Pilosella sedutrix (Rehmann) Schljakov
Pilosella thaumasia (Peter) Dostál
Pilosella thaumasioides (Peter) Schljakov
Pilosella varatinensis (Wo\u0142.) Schljakov
Pilosella viscidula (Tausch) Schljakov^[1]

Mouse-ear Hawkweed (Pilosella officinarum, syn. Hieracium pilosella L.) is a yellow-flowered species of Asteraceae, native to Europe and northern Asia. It produces single, citrus-colored inflorescences. It is an allelopathic plant. Like most hawkweed species, it shows tremendous variation and is a complex of several dozens subspecies and hundreds of varieties and forms.

[edit] Common names

Danish: Håret Høgeurt
Czech: Jestřábník chlupáček
German: Kleines Habichtskraut
Finnish: Huopakeltano
Hungarian: Ezüstös hölgymál
Dutch: Muizenoor
Norwegian: Hårsveve
Polish: Jastrzębiec kosmaczek
Swedish: Gråfibbla
Ukrainian: Нечуйвітер волохатенький

[edit] Description

It is a hispid (hairy) perennial plant, with a basal rosette of leaves. The whole plant, with the exception of the flower parts, is covered in glandular hairs, usually whitish, sometimes reddish on the stem. The rosette leaves are entire, acute to blunt, and range from 1-12 cm long and 0.5-2 cm broad. Their underside is tomentose (covered with hair). The flowering stem (scape) is generally between 5 cm to 50 cm tall, and sprouts from the centre of the basal rosette. The flowerheads are borne singly on the scape and are a pale lemon-yellow colour, with the outermost ligules having a reddish underside.

The plant favours dry, sunny areas. It grows well on sandy and similarly less fertile ground types. It produces stolons are which generate a new rosette at their extremity, each rosette has the possibility of developing into a new clone forming dense mats in open space. It also propagates by seeds.

[edit] Ecology

It is a known allelopathic plant, whose roots secrete several substances inhibiting root growth,^[2] including its own. It can be controlled through rotation with clover and grasses where possible.^[2]

Recent research claims that Hieracium pilosella exhibits an atavism by the reemergence of sexual reproduction.^[3]

[edit] Cultivation and uses

Mouse-ear Hawkweed has become a common introduced invasive species in North America (where it is found in southern Canada and both northeast and northwest U.S.), and New Zealand. It is a level C noxious weed in the United States (with higher levels in the states of Washington and Oregon), and a weed in Quebec. It does not have special designations in other locations of Canada. It is known to be strongly invasive in New Zealand's tussock fields, where there are no native species of hawkweed, and biological control measures are being undertaken to control it and other hawkweed species.

Joseph Pitton de Tournefort mentions that blades covered in this plant's juices were believed to cut through stone as easily as through wood.^[4]

[edit] Medicinal uses

The Mouse-ear Hawkweed contains umbelliferone, a compound similar to coumarin and a known antibiotic against brucellosis,^[5] as well as a frequent active compound in sunscreen lotions. The plant is also a potent diuretic.