Hawkweed
Encyclopedia
Hawkweed refers to any species in the very large genus Hieracium
Hieracium
Hieracium known by its common name Hawkweed and long ago by its classical name hierakion which comes from the ancient Greek hierax, "a hawk"...

and its segregate
Segregate (taxonomy)
In taxonomy, a segregate, or a segregate taxon is created when a taxon is split off, from another taxon. This other taxon will be better known, usually bigger, and will continue to exist, even after the segregate taxon has been split off...

 genus Pilosella, in the sunflower
Sunflower
Sunflower is an annual plant native to the Americas. It possesses a large inflorescence . The sunflower got its name from its huge, fiery blooms, whose shape and image is often used to depict the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, rough leaves and circular heads...

 family (Asteraceae).

They are common perennials
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

, occurring worldwide . They are usually small and weedy. Only a few are ornamental plant
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...

s. Most are considered to be troublesome weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...

s.

They grow to 5–100 cm tall, and feature clusters of yellow, orange or red flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

 heads, similar to dandelions, atop a long, fuzzy stalk.

Hawkweed is a slang name taken from folklore
Folklore
Folklore consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called...

 which says that hawk
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...

s would chew on the plant to improve their eyesight.

Hawkweeds are used as food plants by the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e of some Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...

 species including Autumnal Rustic
Autumnal Rustic
The Autumnal Rustic is a moth of the family Noctuidae. It was previously placed in the genus Paradiarsia. It is found in northern and western Europe....

, Broad-barred White
Broad-barred White
The Broad-barred White is a moth of the family Noctuidae. It is distributed throughout Europe and is also found in Turkey, Iran, Israel, Lebanon, Syria, Kirghizia, Tajikistan, western Siberia and China....

, Dot Moth
Dot Moth
The Dot Moth is a moth of the family Noctuidae. It is found throughout Europe apart from the south-east.This is a very distinctive species with very dark brown, almost black, forewings marked with a large white stigma from which the species gets its common name. The hindwings are grey with a dark...

, Hebrew Character
Hebrew Character
Hebrew Character is a moth species, Orthosia gothica, of the family Noctuidae. It is found throughout Europe.The forewings of this species are greyish to rufous brown. Typically these are marked with a black mark shaped like the Hebrew letter Nun נ). This is similar to the markings of the Setaceous...

, Large Yellow Underwing
Large Yellow Underwing
The Large Yellow Underwing is a moth, the type species for the family Noctuidae. It is an abundant species throughout Europe, one of the most common and most familiar moths of the region. In some years the species is highly migratory with large numbers appearing suddenly in marginal parts of the...

, Lime-speck Pug
Lime-speck Pug
The Lime-speck Pug is a moth of the family Geometridae. It is a common species throughout the Palearctic region, the Near East and North Africa....

, The Shark
Shark (moth)
The Shark is a moth of the family Noctuidae. It is distributed throughout Europe, but has recently also been reported from North America, from the Magdalen Islands in Canada....

, the grass moth Diasemia reticularis
Diasemia reticularis
Diasemia reticularis is a species of moth of the family Crambidae. It is typically found in the tropics, but may range into Europe as far north as the North Sea region because of its migratory nature.The wingspan is 18–22 mm...

, and also by small beetles.

Taxonomy

Few genera are more complex and have given botanists such trouble due to the great number of apomictic
Apomixis
In botany, apomixis was defined by Winkler as replacement of the normal sexual reproduction by asexual reproduction, without fertilization. This definition notably does not mention meiosis...

 species. Through speciation
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...

 by rapid evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

, polyploidy
Polyploidy
Polyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...

, and possibly also hybridisation, this variable genus has given rise to thousands of small variations and more than 10,000 microspecies, each with their own taxonomic name, have been described. The database IPNI
IPNI
The International Plant Names Index is a database of botanical names. It indexes names of seed plants, ferns and "fern allies". Coverage is best at the rank of species and genus...

 provides more than 12,000 named taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

 for this genus, including subspecies and synonyms, but it is far from complete.

Attempts have been made to break up this genus in Hieracium (sensu stricto; retaining most species) and Pilosella (about 16 species), based on achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...

 characters and the occurrence of stolon
Stolon
In biology, stolons are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons.-In botany:...

s.

Species

The list below is a selection of species for which common names are recorded. A more complete list is given in List of Hieracium species.
Hieracium
  • Hieracium albiflorum
    Hieracium albiflorum
    The common wildflower Hieracium albiflorum is known by the names white hawkweed and white-flowered hawkweed.It is found in western North America, from Alaska to California and east to the Rockies...

    - White-flowered Hawkweed
  • Hieracium alpinum - Alpine Hawkweed
  • Hieracium amitsokense - Royal Hawkweed
  • Hieracium angmagssalikense - Blackstyle Hawkweed

  • Hieracium argutum
    Hieracium argutum
    Hieracium argutum is a species of flowering plant in the aster family known by the common name southern hawkweed. It is endemic to California, where it can be found in coastal and inland hills and mountains, often in oak woodland and pine forest habitat...

    - Southern Hawkweed
  • Hieracium atratum - Polar Hawkweed
  • Hieracium aurantiacum - Orange Hawkweed, Devil's Paintbrush
  • Hieracium bolanderi - Bolander's Hawkweed
  • Hieracium bombycinum - Spanish King-devil
  • Hieracium caespitosum
    Hieracium caespitosum
    Hieracium caespitosum...

    - Meadow Hawkweed, Yellow Hawkweed
  • Hieracium canadense - Canadian Hawkweed
  • Hieracium carneum - Huachuca Hawkweed
  • Hieracium cynoglossoides - Houndstongue Hawkweed
  • Hieracium devoldii
    Hieracium devoldii
    Hieracium devoldii, a name for a plant in the hawkweed genus Hieracium, has been identified as a synonym of two different species:*Hieracium canadense*Hieracium laevigatum...

    - Devold's Hawkweed
  • Hieracium fendleri - Yellow Hawkweed
  • Hieracium florentinum - Smooth Hawkweed, King Devil, Pale Hawkweed
  • Hieracium floribundum - Yellow Devil Hawkweed
  • Hieracium glomeratum - Queen Devil Hawkweed

  • Hieracium gracile
    Hieracium gracile
    Hieracium gracile is a species of hawkweed known by the common name slender hawkweed. It is native to much of the northwestern United States and parts of British Columbia, where it grows in moist mountain forests. Two varieties are native to Alaska...

    - Slender Hawkweed
  • Hieracium greenei
    Hieracium greenei
    Hieracium greenei is a species of hawkweed known by the common name Greene's hawkweed....

    - Greene's Hawkweed
  • Hieracium greenii - Maryland Hawkweed
  • Hieracium groenlandicum - Greenland Hawkweed

  • Hieracium gronovii - Queendevil Hawkweed
  • Hieracium horridum - Prickly Hawkweed
  • Hieracium hyparcticum - Arctic Hawkweed
  • Hieracium inuloides - Butterfly Hawkweed
  • Hieracium ivigtutense - Holsteinsborg Hawkweed
  • Hieracium kalmii - Kalm's Hawkweed
  • Hieracium lachenalii
    Hieracium lachenalii
    Hieracium lachenalii also known as Common Hawkweed or Yellow Hawkweed is a woodland perennial which makes its home in fields and on roadsides.-Description:...

    - Common Hawkweed
  • Hieracium laevigatum - Smooth Hawkweed
  • Hieracium lemmonii - Lemmon's Hawkweed
  • Hieracium lividorubens - Cow Hawkweed
  • Hieracium longiberbe - Longbeard Hawkweed

  • Hieracium longipilum - Hairy Hawkweed
  • Hieracium maculatum - Spotted Devil's Paintbrush
  • Hieracium megacephalon - Coastalplain Hawkweed
  • Hieracium musartutense - Musartut Hawkweed
  • Hieracium negrescens - Brocken Hawkweed
  • Hieracium nepiocratum - Lindenows Fjord Hawkweed
  • Hieracium murorum - Wall Hawkweed
  • Hieracium paniculatum - Allegheny Hawkweed
  • Hieracium pilloselloides - Tall Hawkweed, Glaucous King Devil
  • Hieracium plicatum - Boreal Hawkweed
  • Hieracium praealtum - Kingdevil Hawkweed
  • Hieracium pratense - Yellow Hawkweed
  • Hieracium pringlei - Pringle's Hawkweed
  • Hieracium rigorosum - Rockyscree Hawkweed
  • Hieracium robinsonii - Robinson's Hawkweed
  • Hieracium rusby - Rusby's Hawkweed
  • Hieracium sabaudum - New England Hawkweed
  • Hieracium scabrum - Rough Hawkweed
  • Hieracium scholanderi - Kap Farvel Hawkweed
  • Hieracium scouleri - Woollyweed
  • Hieracium snowdoniense - Snowdonia hawkweed
  • Hieracium stelechodes - Dronning Maries Dal Hawkweed
  • Hieracium stiptocaule - Igaliko Fjord Hawkweed
  • Hieracium sylowii - Brownstyle Hawkweed
  • Hieracium tridentatum - Treetooth Hawkweed
  • Hieracium trigonophorum - Singlehead Hawkweed
  • Hieracium triste - Woolly Hawkweed
  • Hieracium umbellatum - Narrowleaf Hawkweed
  • Hieracium venosum - Rattlesnake Weed
  • Hieracium villosum - Shaggy Hawkweed
  • Hieracium wellwitchii - Silver Mouse-ear
  • Hieracium wrightii - Roughstem Hawkweed

Pilosella
  • Pilosella aurantiaca
    Pilosella aurantiaca
    Pilosella aurantiaca is a flowering plant of the family Asteraceae native to alpine regions of central and southern Europe, where it is protected in several regions.It is a low-growing plant with shallow fibrous roots and a basal rosette of elliptical to lanceolate...

    (Hieracium aurantiacum) - Orange Hawkweed
  • Pilosella officinarum (Hieracium pilosella) - Mouse-ear Hawkweed
    Mouse-ear Hawkweed
    Mouse-ear Hawkweed is a yellow-flowered species of Asteraceae, native to Europe and northern Asia. It produces single, citrus-colored inflorescences. It is an allelopathic plant...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK