Daucus is a worldwide genus of herbaceous plants of the celery familyApiaceae of which the best-known species is the cultivated carrot. Daucus has about 25 species. The oldest carrot fossil is 1.3 Ma, and was found in Madeira island
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
Daucuspollination 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 adaptative to these conditions. Some Daucus species accumulate substantial resources in large underground taproots without impeding plant development. Native to Europe is the Carrot, with two subspecies: Wild Carrot and, 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 was present in each Daucusline, 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.
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
