Definitions

hieracium pilocella

Hieracium

Hieracium (pronounced 'hi-er-AS-ee-um') known by its common name Hawkweed and long ago by its classical name hierakion which comes from the ancient Greek hierax, "a hawk" is a genus of the sunflower (Helianthus) family Asteraceae (previously called Compositae) and are closely related to dandelion (Taraxacum), chicory (Cichorium), prickly lettuce (Lactuca) and sow thistle (Sonchus) which are part of the tribe Cichorieae. Hawkweeds with their 10,000+ recorded species and subspecies and approximately 800 accepted species members, do their part to make Asteraceae the second largest family of flowers.

Common names

Hawkweed
Høgeurt
Habichtskräuter
Ukonkeltanot
Sparviere
ヤナギタンポポ属
Vanagė
Havikskruid
Svever
Jastrzębiec (roślina)
Jestřábník
Škržolica
Şahin otu
Нечуйвітер
山柳菊屬

Description

Flowers and flower-heads

Hieracium or Hawkweeds, like the others in the Asteraceae family have mostly yellow, tightly packed flower-heads of numerous small flowers but unlike daisies and sunflowers in the same family, they have not two kinds of florets but only strap-shaped (spatulate#Adjective) florets, each one of which is a complete flower in itself, not lacking stamens, and joined to the stem by leafy bracts. Like other tribe Cichorieae members each ray corolla#Noun is tipped by 3 to 5 teeth.

Bracts, stems and leaves

Erect single, glabrous or hairy stems, sometimes branched away from the point of attachment, sometimes branched throughout.

The hairiness of Hawkweeds can be very complex: from surfaces with scattered to crowded, tapered, whiplike, straight or curly, smooth to seta#Noun; "stellate-pubescent" or surfaces with scattered to crowded, dendritic branched (often called, but seldom truly, "stellate") hairs; and "stipes-gland#Noun" or surfaces with scattered to crowded gland-tipped hairs mostly. Surfaces of stems, leaves, peduncle#Nouns, and phyllaries may be glabrous or may bear one, two, or all three of the types of hairs mentioned here.

Like the others in the Asteraceae family have milky juice when either the leaves or the stems are broken.

See Hieracium anatomy for photographs of miscellaneous Hieracium phytotomy details.

Fruits


Ecology

Large Yellow Underwing (Noctua pronuba)

Distribution

Hieracium can be found throughout the continental United States and Alaska. Mexico, Central America, South America, Europe, Asia, Africa.

Species

the United States

The list below is a selection of species which have been accepted by the USDA Natural Resources Conservation Service. A more complete list is given in List of Hieracium species.

  • Hieracium albiflorum Hook. -- white hawkweed P
  • Hieracium ×alleghaniense Britt. (pro sp.) P
  • Hieracium argutum Nutt. -- southern hawkweed P
  • Hieracium ×atramentarium (Naegeli & Peter) Zahn ex Engl. (pro sp.) P
  • Hieracium atratum Fries -- polar hawkweed P
  • Hieracium aurantiacum L. -- orange hawkweed P
  • Hieracium bolanderi Gray -- Bolander's hawkweed P
  • Hieracium ×brachiatum Berth. ex DC. P
  • Hieracium caespitosum Dumort. -- meadow hawkweed P
  • Hieracium canadense Michx. -- Canadian hawkweed P
  • Hieracium carneum Greene -- Huachuca hawkweed P
  • Hieracium cynoglossoides Arv.-Touv. -- houndstongue hawkweed P
  • Hieracium ×fassettii Lepage P
  • Hieracium fendleri Schultz-Bip. -- yellow hawkweed P
  • Hieracium ×fernaldii Lepage P
  • Hieracium ×flagellare Willd. (pro sp.) P
  • Hieracium ×floribundum Wimmer & Grab. (pro sp.) P
  • Hieracium ×fuscatrum Naegeli & Peter (pro sp.) P
  • Hieracium glomeratum Froel. -- queen-devil hawkweed P
  • Hieracium gracile Hook. -- slender hawkweed P
  • Hieracium greenei Gray -- Greene's hawkweed P
  • Hieracium greenii Porter & Britt. -- Maryland hawkweed P
  • Hieracium ×grohii Lepage P
  • Hieracium gronovii L. -- queendevil'' P
  • Hieracium horridum Fries -- prickly hawkweed P
  • Hieracium kalmii L. -- Kalm's hawkweed P
  • Hieracium lachenalii K.C. Gmel. -- common hawkweed P
  • Hieracium lactucella Wallr. -- European hawkweed P
  • Hieracium laevigatum Willd. -- smooth hawkweed P
  • Hieracium lemmonii Gray -- Lemmon's hawkweed P
  • Hieracium longiberbe T.J. Howell -- longbeard hawkweed P
  • Hieracium longipilum Torr. -- hairy hawkweed P
  • Hieracium maculatum Sm. -- spotted hawkweed P
  • Hieracium marianum Willd. -- Maryland hawkweed P
  • Hieracium megacephalon Nash -- coastal plain hawkweed P
  • Hieracium murorum L. -- wall hawkweed P
  • Hieracium paniculatum L. -- Allegheny hawkweed P
  • Hieracium pilosella L. -- mouseear hawkweed P
  • Hieracium piloselloides Vill. -- tall hawkweed P
  • Hieracium praealtum Vill. ex Gochnat -- kingdevil P
  • Hieracium pringlei Gray -- Pringle's hawkweed P
  • Hieracium robinsonii (Zahn) Fern. -- Robinson's hawkweed P
  • Hieracium rusbyi Greene -- Rusby's hawkweed P
  • Hieracium sabaudum L. -- New England hawkweed P
  • Hieracium scabrum Michx. -- rough hawkweed P
  • Hieracium schultzii Fries -- roughstem hawkweed P
  • Hieracium scouleri Hook. -- Scouler's woollyweed P
  • Hieracium scribneri Small -- Scribner's hawkweed P
  • Hieracium triste Willd. ex Spreng. -- woolly hawkweed P
  • Hieracium umbellatum L. -- narrowleaf hawkweed P
  • Hieracium venosum L. -- rattlesnakeweed P

Europe

See also

References

External links


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