Pilosella officinarum

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Pilosella officinarum
Hieracium pilosella plant.jpg
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Tribe: Cichorieae
Genus: Pilosella
P. officinarum
Binomial name
Pilosella officinarum
  • Hieracium albofloccosum (Nägeli & Peter) Prain
  • Hieracium kemulariae Üksip
  • Hieracium leucopsilon Arv.-Touv.
  • Hieracium melanops (Peter) J.Weiss
  • Hieracium obscurisquamum (Nägeli & Peter) Prain
  • Hieracium paradoxum Kem.-Nath.
  • Hieracium pilosella L.
  • Hieracium tricholepium (Nägeli & Peter) Prain
  • Hieracium trichosoma (Peter) J.Weiss
  • Pilosella angustella Norrl.
  • Pilosella melanops (Peter) Dostál
  • Pilosella micradenophora Dostál
  • Pilosella tricholepia (Nägeli & Peter) Dostál
  • Pilosella urnigera Norrl.

Pilosella officinarum (synonym Hieracium pilosella[1]), known as mouse-ear hawkweed,[2] is a yellow-flowered species of flowering plant in the daisy family Asteraceae, native to Europe and northern Asia. It produces single, lemon-coloured inflorescences. Like most hawkweed species, it is highly variable and is a member of a species complex of several dozens of subspecies and hundreds of varieties and forms. It is an allelopathic plant.


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 centimetres (0.39–4.72 in) long and 0.5–2 centimetres (0.20–0.79 in) broad. Their underside is tomentose (covered with hair). The flowering stem (scape) is generally between 5–50 centimetres (2.0–19.7 in) 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. It flowers from May until August and the flowers are visited by various groups of insects, especially flies.[3]

The plant favours dry, sunny areas. It grows well on sandy and similarly less fertile ground types. It produces stolons 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.


It is a known allelopathic plant, whose roots secrete several substances inhibiting root growth,[4] including its own. It can be controlled through rotation with clover and grasses where possible.[4]

Recent research claims that Pilosella officinarum exhibits an atavism by the reemergence of sexual reproduction.[5]

Similar species[edit]

Shetland mouse-ear hawkweed (Pilosella flagellaris subsp. bicapitata) is similar, but has two flowers per leaf stalk. It is found in the Shetland Islands only, on rocky coastal grassland. It flowers from May to August.[6]

Cultivation and uses[edit]

Mouse-ear hawkweed has become a common introduced invasive species in North America (where it is found in southern Canada and both north-east and north-west United States), 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 similar species. In Victoria and NSW, Australia, Hawkweed Sp. are declared as State Prohibited Weeds and are controlled under The Bio Security Act 2015. Currently there are several eradication programs operating (often employing volunteers) to locate, prevent the spread of and eradicate any Pilosella (Hieracium) sp. plants.

Joseph Pitton de Tournefort mentions that blades covered in this plant's juices were believed to cut through stone as easily as through wood.[7]

Medicinal uses[edit]

The mouse-ear hawkweed contains umbelliferone, a compound similar to coumarin and a known antibiotic against brucellosis,[8] as well as a frequent active compound in sunscreen lotions. The plant is also a potent diuretic.

Image gallery[edit]


  1. ^ a b c "Pilosella officinarum Vaill.". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2019-01-29.
  2. ^ "Hieracium pilosella". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 31 January 2016.
  3. ^ Van Der Kooi, C. J.; Pen, I.; Staal, M.; Stavenga, D. G.; Elzenga, J. T. M. (2015). "Competition for pollinators and intra-communal spectral dissimilarity of flowers". Plant Biology. 18 (1): 56–62. doi:10.1111/plb.12328. PMID 25754608.
  4. ^ a b Carol Piening (1988-08-29). "Element Stewardship Abstract for Hieracium Pilosella". The Global Invasive Species Initiative. Archived from the original on 2006-09-18. Retrieved 2006-11-17.
  5. ^ Science News, vol. 171, p. 302
  6. ^ Rose, Francis (2006). The Wild Flower Key. Frederick Warne & Co. pp. 480–481. ISBN 978-0-7232-5175-0.
  7. ^ Hieracium pilosella in the online Flore Laurentienne
  8. ^ Bishop, G. F.; A. J. Davy (1994). "Hieracium pilosella L. (Pilosella officinarum F. Schultz & Schultz-Bip.)". Journal of Ecology. 82 (1): 195–210. doi:10.2307/2261400. JSTOR 2261400.

External links[edit]