Carrot family (Apiaceae)
Description: This plant is a winter or spring annual that becomes about 2' tall, branching occasionally. The stems are slender and round. They are more or less covered with fine hairs that are white and short. The alternate leaves are pinnately or bipinnately compound, and have petioles that are long and slender. These leaves have a triangular shape in outline and a fern-like appearance, spanning up to 6" long and 4" across (excluding the petioles) and becoming smaller in size as they ascend the stems. Some of the upper leaves near the inflorescence are lanceolate or narrowly ovate. The leaflets of the compound leaves are trifoliate. They have rather slender with wedge-shaped bottoms, while their margins are cleft or coarsely toothed. The upper surface of each leaflet is sparsely covered with short white hairs.
The upper stems terminate in compound umbels of small white flowers on long naked stalks. Each compound umbel is about 2–3" across, consisting of about 8 umbellets. The base of each compound umbel is usually without bracts, although sometimes there is a single linear bract. An umbellet has about 8 flowers and a similar number of small linear bracts at its base. Each flower is about 1/8" (3 mm.) across, with 5 white petals and 5 stamens. The blooming period usually occurs from early to mid-summer and lasts about a month. This plant has a tendency to sprawl because of the weight of the umbels of flowers on their long slender stalks. Upon maturity, each flower is replaced by a single seed. This seed is oblong and has a bur-like covering of bristles. It is initially rosy to whitish green in appearance, but later turns brown. The bristles are straight to slightly curved; they do not have hooked tips. The root system consists of a taproot. This plant spreads by a reseeding itelf, and it often forms colonies.
Cultivation: The preference is full sun, mesic to dry conditions, and a rather heavy soil containing gravel or clay. Because this plant often grows in soil containing limestone gravel, it appears to tolerate alkaline conditions. It matures quickly during the growing season, produces flowers and seeds, and then dies, although the stems remain more or less erect for some time.
Range & Habitat: The non-native Common Hedge Parsley occurs primarily in southern, central, and NE Illinois, where it is occasional to locally common. In NW Illinois, it is rare or absent (see Distribution Map). This species is adventive from Eurasia, and it appears to be spreading throughout the state. Habitats include thickets, woodland borders, weedy meadows, areas along railroads and roadsides, gravelly areas along streams, and waste areas. Disturbed habitats are preferred, including degraded prairies and woodlands that have been recently logged.
Faunal Associations: Like other members of the Carrot family, the small white flowers attract various insects, including small bees, flies, wasps, and beetles. The caterpillars of the butterfly Papilio polyxenes asterius (Black Swallowtail) feed on the foliage. The bur-like covering of the seeds clings readily to the fur of mammals, the feathers of birds, and the clothing of humans. Thus, animals help to distribute the seeds far and wide. The foliage is not known to be toxic, and it may be eaten occasionally by mammalian herbivores.
Photographic Location: The edge of a degraded prairie along a railroad where there is an abundance of limestone gravel in Savoy, Illinois.
Comments: Common Hedge Parsley grows in similar habitats and has a similar appearance to Daucus carota (Wild Carrot). However, it is a shorter plant that blooms earlier in the year. The leaves and stems of Common Hedge Parsley are more or less covered with fine white hairs, while the foliage of Wild Carrot is nearly hairless. Even more significantly, the floral bracts of Common Hedge Parsley are either absent or inconspicuous, while the floral bracts of Wild Carrot are quite long, abundant, and conspicuous. The most distinctive characteristic of Torilis spp. is the bur-like seeds, which are often rosy-green in appearance and have a dense covering of fine bristles. It can be a major inconvenience to walk through a colony of these plants, as the abundant bur-like seeds cling tenaciously to clothing and are difficult to remove. For a long time, Common Hedge Parsley was incorrectly identified as Torilis japonica (Japanese Hedge Parsley). However, this latter species has about 8 linear bracts at the base of each compound umbel, and the bristles of its seeds have hooked tips. While Japanese Hedge Parsley occurs in Illinois, it far less common than Common Hedge Parsley. As a result of this misidentification, the distribution records within the state include observations of both species.