Carrot family (Apiaceae)
Description: This adventive biennial plant consists of a rosette of basal leaves during the first year, bolting upward during the second year to produce flowers and seeds. Mature second-year plants are about 2-3½' tall. The basal leaves are usually double pinnate with long petioles. In outline, they are up to 10" and 4" across (including the petioles), narrowing gradually toward their tips. Each compound leaf is subdivided into leaflets that are usually pinnate, while the secondary leaflets are entire, cleft, or coarsely toothed. The individual leaflets are rather narrow, providing the compound leaves with a lacy or fern-like appearance. Scattered white hairs often occur along the petioles, or along the margins and lower mid-veins of the leaflets. The round stems of bolting plants are finely ribbed and have scattered white hairs; they are hollow on the inside and branch sparingly. The compound leaves along the stems are alternate and have their petioles enclosed by sheaths. Otherwise, they are similar to the basal leaves in appearance.
The flowering stalks are long and largely devoid of leaves, terminating in compound umbels of small white flowers. Each compound umbel has a whorl of green bracts at its base that are pinnatifid with linear segments. The flat-topped compound umbel is about 2-5" across and consists of about 30 umbellets. Each umbellet has a whorl of linear green bracts at its base and consists of about 30 flowers. While the flowers are blooming, their slender pedicels are often white or greenish white. Each flower consists of 5 white petals and 5 stamens, spanning about 1/8" across. However, the central flower of the central umbellet is often reddish purple. There are forms of Wild Carrot where all of the flowers are light pink, light purple, or reddish purple; the latter color is particularly rare. The blooming period occurs from mid-summer to early fall and lasts about 2 months. There is no noticeable floral scent, although the foliage has a slightly bitter carrot-like scent because of the presence of saponins and possibly other chemicals.
Each flower produces a 2-seeded burry fruit about 1/8" long that is ovoid in shape. Each seed is flat on one side, but rounded on the other, and it has white bristly hairs along its ribs. The fruits are variable in color; they are initially light reddish purple, later becoming grayish brown. As the seeds become mature, the compound umbels start to close and assume a shape that is more or less spheroid. They can become detached from the flowering stalks and blow about in the wind. The root system consists of a stout taproot that is white and runs deep into the ground. This plant spreads by reseeding itself.
Cultivation: This species usually grows in locations with full sunlight, mesic to dry conditions, and a clay-loam soil that is not too acidic. However, it will also adapt to moist conditions and other kinds of soil. Wild Carrot is aggressive and can be difficult to destroy. It often survives mowing and hand-pulling of plants by the rootstocks. This is because the deep taproot is difficult to remove and stores considerable energy to initiate new growth.
Range & Habitat: Wild Carrot is a very common plant that occurs in every county of Illinois (see Distribution Map). It is adventive from Europe and has existed in the United States for quite some time. Habitats include thickets, degraded prairies or meadows, areas along railroads and roadsides, lawns, pastures, abandoned fields, fence rows, vacant lots, junk yards, and other waste areas. Fire is not very effective in removing this plant from natural habitats, however it tends to decline in such habitats in the absence of disturbance.
Faunal Associations: The nectar of the flowers attracts many kinds of insects, especially flies and wasps, including parasitoid Gasteruption spp. (Wild Carrot Wasps). The foliage is eaten by the caterpillars of the butterfly Papilio polyxenes asterias (Black Swallowtail). The burry fruits can be spread by birds and mammals by clinging to their feathers or fur. It has also been shown that the seeds can pass through the digestive tracts of livestock and remain viable, which provides another method of distribution. Although the foliage and flowers are not preferred as a source of food for mammalian herbivores, it is eaten occasionally by rabbits, deer, and cattle. With the exception of the Ring-Necked Pheasant, most birds don't use the seeds as a food source. Blue Jays have been known to use the foliage of Wild Carrot in the construction of their nests. This practice appears to be beneficial, as it reduces the number of nest lice and other parasites, producing healthier hatchlings with a higher survival rate. Apparently, the foliage of Wild Carrot contains an insecticide or insect repellant.
Photographic Location: A weedy meadow at Judge Webber Park in Urbana, Illinois.
Comments: Wild Carrot is an ubiquitous plant that many people can recognize. It is possible, however, to confuse this introduced species with other white-flowered members of the Carrot family. Wild Carrot doesn't begin blooming until mid-summer and usually occurs in mesic to dry areas, rather than wetlands. The presence of a single reddish purple flower in the middle of the compound umbel is a distinctive characteristic, although it is not always present. There is a similar native species, Daucus pusillus (Small Wild Carrot), that occurs in two counties of southern Illinois. The primary bracts of the compound flowers for this species are double pinnate, whereas the primary bracts of the introduced species are single pinnate. According to most authorities, Wild Carrot is the source of the cultivated carrot. In addition, this species is the source of the natural food dye, carotene, which provides it with additional commercial importance. Another common name of Daucus carota is Queen Anne's Lace.