Buttercup family (Ranunculaceae)
Description: This perennial wildflower is 4-8" tall. A non-flowering plant produces a whorl of trifoliate basal leaves on slender stems; each basal leaf typically has 3 leaflets on a long slender petiole. The basal stems are light green to reddish purple, unbranched, terete, and hairless; the stems of flowering plants are similar. Individual leaflets are up to 1½" long and 1" across; they are obovate or broadly oblong in shape. The outer margin of each leaflet has 3 blunt lobes, otherwise the margins are usually smooth. Sometimes there are 1-2 blunt teeth along the outer margin of a leaflet. The upper surface of each leaflet is medium green to purplish green and hairless, while the lower surface is pale green and hairless. A reticulate network of veins is conspicuous on the lower surface. At the base of each leaflet, there is a slender stalk (petiolule) about ¼" long. Toward the middle of its stem, a flowering plant sometimes produces a whorl of cauline leaves that resembles the whorled basal leaves. At its apex, this stem terminates in a whorl of trifoliate leaves or simple leaflets (sometimes including a combination of the two). These terminal leaves and leaflets resemble the leaves and leaflets of the basal and cauline leaves. Immediately above the terminal leaves or leaflets is a loose umbel of 1-5 flowers. The slender pedicels of the flowers are up to 1½" long. The diurnal flowers are ½–1" across; the central flower is usually a little larger in size than any lateral flowers. Each flower has 5-10 petal-like sepals, a dense cluster of small green pistils in the center, and a ring of conspicuous stamens. The petal-like sepals are white or pinkish white, while the stamens have white filaments and yellow anthers. There are no true petals. The blooming period occurs from mid- to late spring for about 3 weeks. Each flower is replaced by a cluster of 4-15 achenes. Each achene is about 1/3" in length, terminating in a slightly hooked beak. Inside each achene, there is a single seed. The root system consists of fibrous roots; the upper roots near the base of a plant are somewhat fleshy and swollen. This wildflower spreads by reseeding itself.
Cultivation: Rue Anemone is best planted under deciduous trees. It prefers dappled sunlight during the spring, but tolerates considerable shade later in the year. Moisture levels should be mesic to slightly dry, and the soil should contain loose loam and rotting organic material. Most growth and develop occurs during the spring; it is not aggressive.
Range & Habitat: Rue Anemone is occasional throughout Illinois (see Distribution Map), where it is native. Habitats include mesic to dry deciduous woodlands, wooded slopes, and thinly wooded bluffs. This wildflower is usually found in above-average to high quality woodlands where the original ground flora is largely intact.
Faunal Associations: The flowers offer only pollen as a reward to insect visitors. Typical floral visitors include various bees, Syrphid flies, and bee flies (Bombyliidae); the bees usually collect pollen, while the flies feed on pollen. Some of these insects explore the showy flowers for nectar in vain. Honeybees, little carpenter bees (Ceratina spp.), cuckoo bees (Nomada spp.), mason bees (Osmia spp.), Halictid bees, and Andrenid bees have been observed as visitors to the flowers. Because the foliage is toxic and relatively inconspicuous, it is usually ignored by mammalian herbivores.
Photographic Location: Near the top of a wooded slope in Vermilion County, Illinois.
Comments: Rue Anemone (Anemonella thalictroides) is one of many showy wildflowers that develop in deciduous woodlands during the spring. Both the flowers and foliage are quite attractive. Because the flowers move around easily in the wind, it is sometimes called 'Windflower.' Another scientific name of this species is Thalictrum thalictroides. Rue Anemone resembles Enemion biternatum (False Rue Anemone), but its flowers have more petaloid sepals (typically 6-9), while the flowers of False Rue Anemone have only 5 petaloid sepals. Furthermore, its leaves and flowers are arranged in whorls to a greater extent than those of False Rue Anemone. While Rue Anemone is sometimes assigned to the Thalictrum genus, other Thalictrum spp. in Illinois are much larger plants with wind-pollinated dioecious flowers. The leaflets of these species are similar to those of Rue Anemone, however their flowers are quite distinct.