Daucus is a worldwidegenus of herbaceous plants of thecelery familyApiaceae of which the best-known species is the cultivatedcarrot.Daucus has about 45 species.[1] The oldest carrot fossil is 1.3Ma, and was found on the island ofMadeira in the Atlantic Ocean.[2]
Members ofDaucus are distinguished within the familyApiaceae by their leaves which are 2–3 pinnatisect with narrow end sections. The genus primarily consists of biennial plants but also includes some annual plants and some perennial herbs. AllDaucus have bristly stems. The inflorescences areumbels. The flowers are mostly white, with bracts and bracteoles. The petals may be pure white, reddish, pinkish or yellowish. They areemarginate above and have pointed, wrapped lobules. The petals are often unequal in size, with petals at the outermost edge of the inflorescence often being larger. The fruit is an ovoid to ellipsoidalschizocarp, cylindrical or compressed, with ciliate primary ribs and secondary ribs with a row of hooked spines.[3] Some species have a small pale or white edibletaproot, similar to a radish, which may or may not be bitter in taste.
Daucuspollination is carried out by insects, primarily:Lepidoptera,Coleoptera,Diptera, andHymenoptera.It is acosmopolitan genus with endemic species on most continents as well as on many islands and in isolated areas.[citation needed] The genus centre is inNorth Africa andSouthwest Asia in the Temperate Zone.[citation needed] Prolonged dry or cold weather tends to retard growth inDaucus species, but the genus as a whole is evolutionarily adaptive to these conditions.[citation needed] SomeDaucus species accumulate substantial resources in large underground taproots without impeding plant development.[citation needed] Native to Europe is thecarrot, with several subspecies, including subsp. carota (wild carrot), subsp. gummifer (sea carrot) and subsp.sativus, a cultivated form of carrot, also called garden carrot).
Four members of the Daucus genus were examined to determine differences in isoenzyme patterns and plastid DNA. The four were:Daucus carota subspeciessativus cultivar Danvers,D. carota subsp.gummifer,D. capillifolius, andD. pusillus. Although only one form of HSDH (homoserine dehydrogenase) was present in eachDaucus 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 eachDaucus 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 andD. pusillus plastid DNA patterns. No differences were found between cv. Danvers andD. capillifolius plastid DNA patterns when examined using eight different restriction enzymes. The data indicate that specific isoenzyme and organelle DNA restriction fragment patterns will be useful markers for precise identification of genomes of differentDaucus species.[4]
Daucus montanusHumb. & Bonpl. ex Spreng. – Mexico to Central America and the Andes
Daucus muricatus(L.) L. – Azores and western and central Mediterranean
Daucus pedunculatus(Baker f.) Banasiak, Spalik & Reduron – eastern tropical Africa from central Ethiopia to Mozambique
Daucus pumilus(L.) Hoffmanns. & Link – Mediterranean basin and the Canary Islands
Daucus pusillusMichx. (syn.D. arcanusF.García Mart. & Silvestre) – American wild carrot; western Canada to northern Mexico and the southeastern US, and southeastern Brazil to southern South America
Daucus reboudiiCoss. ex Batt. – northern Algeria and Tunisia
^Benjamin F. Matthews; Kenneth G. Wilson; Lorin R. DeBonte (January 1984). "Variation in Culture, Isoenzyme Patterns and Plastid DNA in the Genus Daucus".In Vitro.20 (1):38–44.doi:10.1007/BF02633330.JSTOR4292775.S2CID42829077.
^Ogren, Thomas Leo (2015).The Allergy-Fighting Garden. Berkeley: Ten Speed Press.ISBN9781607744917.
