Daucus
Encyclopedia
Daucus is a worldwide genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of herbaceous plants of the family Apiaceae
Apiaceae
The Apiaceae , commonly known as carrot or parsley family, is a group of mostly aromatic plants with hollow stems. The family is large, with more than 3,700 species spread across 434 genera, it is the sixteenth largest family of flowering plants...

 of which the best-known species is the cultivated carrot
Carrot
The carrot is a root vegetable, usually orange in colour, though purple, red, white, and yellow varieties exist. It has a crisp texture when fresh...

. Daucus genus of Umbelliferae Apiaceae, has about 25 species.

Features

They differ in the family Apiaceae by their leaves 2-3 pinnatisect. The end sections are always narrow. The Daucus genus are annual plants or mostly biennial plants or also perennial herbs, with a bristly stem. The inflorescences are umbels. The umbrel flowers are mostly white, with bracts and bracteoles. The tiny 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...

s are a compounded. The petals are pure white, reddish, pinkish or yellowish. They are emarginate above and have a pointed, wrapped lobules. The petals are often unequal in size, and the outermost edge of the flower is often brilliant. The fruit is ovoid to ellipsoidal, and cylindrical or compressed. The fruits have ciliated primary ribs and secondary ribs have a row of spines.
Some species are having pale or white, small edible root radish-like, bitter or not.

Ecology

The pollination
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...

 is carried by insects: 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...

, Coleoptera, Diptera
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...

, and Hymenoptera
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...

.
It is a worldwide genus with endemic species on islands and isolated areas. The genus centre is in North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...

, and Southwest Asia
Southwest Asia
Western Asia, West Asia, Southwest Asia or Southwestern Asia are terms that describe the westernmost portion of Asia. The terms are partly coterminous with the Middle East, which describes a geographical position in relation to Western Europe rather than its location within Asia...

 in the Temperate Zone. Prolonged dry or cold weather retard growth but result in adaptative strategy in the genus evolution. Stages of development not suffers due to the accumulation of resources by underground in the root in some species.
Genus Daucus is represented in the Macaronesian Islands by endemic species of wide distribution. Native to Europe is only Carrot
Carrot
The carrot is a root vegetable, usually orange in colour, though purple, red, white, and yellow varieties exist. It has a crisp texture when fresh...

 species with the two subspecies: Wild Carrot
Wild carrot
Daucus carota is a flowering plant in the family Apiaceae, native to temperate regions of Europe, southwest Asia and naturalised to northeast North America and Australia; domesticated carrots are cultivars of a subspecies, Daucus carota subsp...

 and (subsp carota Daucus carota), a cultivated form of carrot
Carrot
The carrot is a root vegetable, usually orange in colour, though purple, red, white, and yellow varieties exist. It has a crisp texture when fresh...

, also garden carrot.

Four members of the Daucus genus were examined to determine differences in isoenzyme patterns, and plastid DNA. The four were: Daucus carota subspecies sativus cultivar Danvers, D. carota subsp. gummifer, D. capillifolius, and D. pusillus. Although only one form of HSDH (homoserine dehydrogenase) was present in each Daucus line, the rate of migration of HSDH from cv. Danvers was different from that of the others. Multiple isoenzymic forms of ADH were present in each Daucus cultivar. Comparison of endonuclease restriction fragment patterns from plastid DNAs digested by BamHI revealed only small differences between plastid DNAs of cv. Danvers and subsp. gummifer, whereas large differences were observed between cv. Danvers and D. pusillus plastid DNA patterns. No differences were found between cv. Danvers and D. capillifolius plastid DNA patterns when examined using eight different restriction enzymes. The data indicate that specific isoenzyme and organeile DNA restriction fragment patterns will be useful markers for precise identification of genomes of different Daucus species.

Systematics

The genus comprises about 20 species divided into three sections. The species include:
  • Daucus aureus Desfontaines, yellow fruit's carrot, golden carrot
  • Daucus azoricus - referred to as Salsa burra, this plant is endemic to the archipelago of the Azores
    Azores
    The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...

  • Daucus broteri Tenore, Brotero's carrot
  • Daucus bicolor Sibthorp & Smith
  • Daucus carota L., Wild carrot
  • Daucus durieui Lange, Durieu's carrot
  • Daucus foliosus Gussone
  • Daucus glochidiatus
    Daucus glochidiatus
    Daucus glochidiatus, commonly known as Australian Carrot, Austral Carrot or Native Carrot, is a species of herb in the flowering plant family Apiaceae. It is native to Australia and New Zealand.-Description:...

    (La Billardière) Fisch., C.A.Mey. & Avé-Lall.
  • Daucus gadeceaui Rouy and Camus., Gadeceau's carrot
  • Daucus guttatus Sibthorp & Smith
  • Daucus involucratus
  • Daucus littoralis Sibthorp & Smith
  • Daucus muricatus (L.) L.
  • Daucus pulcherrima
  • Daucus pusillus
    Daucus pusillus
    Daucus pusillus is a species of wild carrot known by the common names American wild carrot and rattlesnake weed. It is similar in appearance to other species and subspecies of wild carrot, with umbels of white or pinkish flowers....

    Michx., American wild carrot
  • Daucus visnaga L.

External links

  • [Http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?3418 species list] on the Germplasm Resources Information Network
  • [Http://www2.dijon.inra.fr/flore-france/da-dh.htm] Index synonymique France: Daucus - Synonyms (French)
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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