Carrot family (Apiaceae)
Description: This plant is a winter or spring annual about ½–1½' tall. Several branching stems develop from the base of the plant; they often sprawl across the ground or lean on adjacent vegetation for support. The stems are light green to purplish green, more or less hairy, and shiny; the hairs occur in lines along the stems or in tufts where the stems branch. The blades of the alternate leaves are up to 4" long and 2" across; they are medium green, hairless to mostly hairless, double-pinnate, and triangular-lanceolate in shape. The pinnatifid leaflets are shallowly to deeply cleft and their tips are obtuse. The petioles of the lower leaves are about as long as the blades, while the upper leaves have short petioles or they are nearly sessile. A membranous sheath wraps around the base of each petiole.
The upper stems terminate in compound umbels of small white flowers. The typical compound umbel has about 3 umbellets, and each umbellet has 3-7 flowers; the divergent stalks of the umbels and umbellets are green and glabrous. The flowers often bloom before the compound umbels have fully expanded. Each flower is less than 1/8" across; it has 5 white petals, 5 stamens, a divided style, insignificant sepals, and a cylindrical green ovary. The blooming period occurs from mid-spring to early summer. Upon reaching maturity, each flower is replaced by a single-seeded fruit. The fruits are about ¼" long, narrowly oblongoid-ellipsoid, and broadest toward the middle; usually the fruits are glabrous, although less often they are finely pubescent. Each fruit has a few longitudinal ridges that are broad and flat; these ridges are separated by narrow grooves. The root system consists of a taproot. This plant spreads by reseeding itself.
Cultivation: The preference is partial sun, moist conditions, and a fertile loamy soil. This species is somewhat weedy.
Range & Habitat: The native Wild Chervil is common in most areas of Illinois (see Distribution Map). Typical habitats include lowland woodlands, open woodlands, woodland borders, thickets, rocky glades, areas adjacent to buildings, and areas along roads and railroads. Habitats with a history of disturbance and some shade are preferred.
Faunal Associations: The flowers are occasionally visited by small bees (especially Halictid bees), parasitic wasps, flies (especially Syrphid flies), and beetles. These insects usually suck nectar from the flowers, although some bees also collect pollen. The caterpillars of the butterfly Papilio polyxenes asterias (Black Swallowtail) feed on the foliage.
Photographic Location: Along a building on the campus of the University of Illinois in Urbana, Illinois. The photographed plant is the typical variety, Chaerophyllum procumbens procumbens.
Comments: The foliage of this native wildflower is similar to cultivated species of parsley and chervil. Cultivated Parsley is a biennial that doesn't naturalize in Illinois because its rosettes are unable to survive the cold weather of winter. However, Anthriscus cerefolium (Cultivated Chervil) and Anthriscus sylvestris (Bur Chervil) occasionally naturalize in Illinois (especially the latter species). Unlike Wild Chervil, both Cultivated and Bur Chervil lack bractlets underneath their umbellets. The species Chaerophyllum tainturieri (Southern Wild Chervil), which occurs in southern Illinois, is even more similar to Wild Chervil than the preceding species. The single-seeded fruits of Southern Wild Chervil are broadest below the middle and the pedicels of its flowers/fruits have a wider diameter toward the top than the bottom. In contrast, the single-seeded fruits of Wild Chervil are broadest toward the middle and the pedicels of its flowers/fruits have the same diameter throughout. Two varieties of Wild Chervil have been described: the typical variety, Chaerophyllum procumbens procumbens, has glabrous fruits, while Chaerophyllum procumbens shortii has fruits that are finely pubescent. This latter variety is less common in Illinois than the typical variety.