Daucus is a worldwide genus of herbaceous plants of the celery family Apiaceae of which the best-known species is the cultivated carrot. Daucus has about 45 species. The oldest carrot fossil is 1.3Ma, and was found on the island of Madeira in the Atlantic Ocean.

Description

Members of Daucus are distinguished within the family Apiaceae 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. All Daucus have bristly stems. The inflorescences are umbels. The flowers are mostly white, with bracts and bracteoles. The petals may be pure white, reddish, pinkish or yellowish. They are emarginate 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 ellipsoidal schizocarp, cylindrical or compressed, with ciliate primary ribs and secondary ribs with a row of hooked spines. Some species have a small pale or white edible taproot, similar to a radish, which may or may not be bitter in taste.

Ecology

Daucus pollination is carried out by insects, primarily: Lepidoptera, Coleoptera, Diptera, and Hymenoptera. It is a cosmopolitan genus with endemic species on most continents as well as on many islands and in isolated areas. The genus centre is in North Africa and Southwest Asia in the Temperate Zone. Prolonged dry or cold weather tends to retard growth in Daucus species, but the genus as a whole is evolutionarily adaptive to these conditions. Some Daucus species accumulate substantial resources in large underground taproots without impeding plant development. Native to Europe is the carrot, 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 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 organelle DNA restriction fragment patterns will be useful markers for precise identification of genomes of different Daucus species.

Species

45 species are currently accepted.

• Daucus aleppicus – Lebanon and Syria

• Daucus aureus – yellow fruit's carrot, golden carrot; Mediterranean basin and Canary Islands

• Daucus bicolor

• Daucus biseriatus – Algeria and Morocco

• Daucus broteri – Brotero's carrot; southeastern Europe to Iran

• Daucus carota – wild carrot, Queen Anne’s lace; Europe, Northern Africa, western and Central Asia, southern China, introduced elsewhere

• Daucus conchitae – Dodecanese and southwestern Turkey

• Daucus crinitus – Iberian Peninsula and northwestern Africa

• Daucus decipiens – Madeira

• Daucus della-cellae – Libya

• Daucus durieua – Durieu's carrot; Canary Islands, Iberian Peninsula, North Africa, Levant

• Daucus edulis – Madeira and Selvagens

• Daucus elegans – Canary Islands

• Daucus glaber – eastern Mediterranean to northern Iran

• Daucus glochidiatus – Australia and New Zealand

• Daucus gracilis – Algeria

• Daucus guttatus – eastern Mediterranean to Iran

• Daucus hochstetteri – Eritrea and Ethiopia

• Daucus humilis – Cape Verde

• Daucus incognitus – eastern tropical Africa from Ethiopia to Mozambique

• Daucus insularis – Cape Verde

• Daucus involucratus – southern and eastern Greece to Crete and western and southern Turkey, Cyprus, and central Israel

• Daucus jordanicus Libya, and Syria to Jordan

• Daucus mauritii – northern Morocco

• Daucus melananthus – central and eastern tropical Africa, Yemen, Madagascar, and South Africa

• Daucus microscias – northern Iraq to northwestern and north-central Iran

• Daucus minusculus – Morocco, Portugal, and Sardinia

• Daucus mirabilis – northeastern Libya

• Daucus montanus – Mexico to Central America and the Andes

• Daucus muricatus – Azores and western and central Mediterranean

• Daucus pedunculatus – eastern tropical Africa from central Ethiopia to Mozambique

• Daucus pumilus – Mediterranean basin and the Canary Islands

• Daucus pusillus (syn. D. arcanus ) – American wild carrot; western Canada to northern Mexico and the southeastern US, and southeastern Brazil to southern South America

• Daucus reboudii – northern Algeria and Tunisia

• Daucus ribeirensis – Cape Verde

• Daucus rouyi – Corsica, Sardinia, Algeria, and Tunisia

• Daucus sahariensis – Morocco to Libya and Sinai

• Daucus setifolius – southern Spain and northwestern Africa

• Daucus setulosus – southeastern Europe to western Turkey, Syria and Lebanon, and northwestern Libya

• Daucus subsessilis – Cyprus, the Levant, southern Iran, and the northeastern Arabian Peninsula

• Daucus syrticus – Tunisia, Libya, and northern Egypt

• Daucus tenuisectus – southwestern Morocco

• Daucus virgatus – Algeria and Tunisia

Allergenicity

Daucus has an OPALS allergy scale rating of 10 out of 10, indicating extremely high potential to cause allergic reactions.

References

The article is based on the following sources:

• Seybold Siegmund (eds): interactive Schmeil-Fitschen (CD-Rom), Source & Meyer, Wiebelsheim 2001/2002,

• , Flora of China

External links

• on the Germplasm Resources Information Network

• Daucus - Synonyms Index synonymique France (French)