Rose family (Rosaceae)
Description: This is a herbaceous perennial plant about ½–2' tall that branches occasionally. The stems are light green to pale red, terete, slightly hairy, and shiny. Both basal and alternate leaves are produced. Basal leaves are compound or simple with long petioles; compound leaves are odd-pinnate with 3-7 leaflets. Simple leaves are orbicular, shallowly cleft, and dentate; the leaflets of compound leaves are ovate, shallowly or deeply cleft, and dentate. Alternate leaves are usually trifoliate with short petioles; their leaflets are narrowly ovate, cleft, and dentate. The upper surfaces of these leaves are medium to dark green and hairless to hairy. At the base of each leaf, there is a pair of large leafy stipules; these stipules are deeply cleft and dentate along their margins.
Flowers develop from the upper stems on long branching stalks; each stalk terminates in an individual flower about ¼" across. Individual flowers also develop from the axils of the upper leaves on long unbranched stalks. These flowering stalks are slightly hairy, shiny, and terete like the stems. Each flower has 5 yellow petals, 5 light green sepals, and a dense cluster of pistils and stamens in the middle. The petals are about the same length as the sepals (less than 1/8" or 3 mm.); the sepals are ovate and hang downward from the rest of the flower. The blooming period occurs from mid- to late spring and lasts about 3 weeks; only a few flowers are in bloom at the same time. Each flower is replaced by dense cluster of bristly achenes; the receptacle of this clustered fruit is exerted from the calyx on a short stout stalk. The individual achenes are ellipsoid in shape and hairless to pubescent; the hooked bristles at their tips are persistent styles. The root system is fibrous and rhizomatous.
Cultivation: The preference is dappled sunlight to light shade, moist to mesic conditions, and a rich loamy soil. Most growth and development occurs during the spring.
Range & Habitat: The native Spring Avens is common in the southern half of Illinois, while in the northern half of the state it is occasional, uncommon, or absent (see Distribution Map). Habitats include rich deciduous woodlands, open woodlands, areas along woodland paths, shaped seeps, woodland borders, and fence rows with woody vegetation. Spring Avens can be found in both disturbed and undisturbed areas that receive some shade.
Faunal Associations: The flowers attract small bees primarily, including little carpenter bees, Halictid bees, cuckoo bees (Nomada spp.), and masked bees (Hylaeus spp.); these small bees suck mostly nectar, although some of the Halictid bees collect pollen for their larvae. Occasionally, Syrphid flies, Tachinid flies, and other flies also visit the flowers. The leaves of Spring Avens and other woodland Geum spp. (Avens) are grazed sparingly by White-tailed Deer. The bristly achenes can cling to the fur of mammals, feathers of birds, and clothing of humans. By this means, they are distributed into new areas.
Photographic Location: A floodplain woodland in Vermilion County, Illinois.
Comments: This is the first woodland Geum sp. (Avens) to bloom in Illinois. Because the yellow petals of its flowers are quite small and short-lived, Spring Avens is not very showy. In contrast, its leaves are moderately attractive and variable in shape. Other woodland species in this genus include Geum canadensis (White Avens) and Geum laciniatum (Rough Avens). These species have flowers with white or cream petals and they bloom a little latter in the year (late spring to early summer). Unlike other species in the genus, the bristly fruits of Spring Avens are exserted from their calyces on short stout stalks. The fruits of other Avens lack these stalks. Thus, Spring Avens is easily identified by this peculiar characteristic.