rue anemone (Thalictrum thalictroides)
Anemonella thalictroides (L.) Spach
Syndesmon thalictroides (L.) Hoffmgg. ex Britt.
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of rue anemone
is Thalictrum thalictroides (L.) Eames & B. Boivin. In genus Thalictrum,
Thalictrum thalictroides is unique in having umbelliform inflorescences
and is therefore easy to identify. Based on this one distinction, many
botanists still place it in the genus Anemonella . The leaflets, flowers, and
fruits, however, are are more in common with those of genus Thalictrum.
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
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This native 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 flow-
ering plants are similar.
Leaves: Individual leaflets are up to 1½" long and 1" across; they are ob-
ovate 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 resem-
bles 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.
Flowers: Immediately above the terminal leaves or leaflets is a loose um-
bel 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
Fruit/Seeds: 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. In-
side each achene, there is a single seed.
Roots: The root system consists of fibrous roots; the upper roots near the
base of a plant are somewhat fleshy and swollen.
REGENERATION PROCESS: Rue anemone propogates itself by re-
HABITAT TYPES: Habitats include mesic to dry deciduous woodlands,
wooded slopes, thinly wooded bluffs, banks, and thickets. This native
wildflower is usually found in above-average to high quality woodlands
where the original ground flora is large.
SITE CHARACTERISTICS: Rue anemone prefers dappled sunlight
during the spring, but tolerates considerable shade later in the year. Pre-
ferred moisture levels are mesic to slightly dry, and prefers soil contain-
ing loose loam and rotting organic material. Most growth and develop
occurs during the spring; it is not aggressive. It is a lowland species,
growing from sea level to about 900 feet.
SEASONAL DEVELOPMENT: The blooming period occurs from mid-
to late spring (May through June) for about 3 weeks.
GENERAL DISTRIBUTION: Rue anemone is primarily a species of
the eastern United States and the mid-west. It is found from Florida north
to Maine, and extends as far west as Texas and Oklahoma, and eastern
Great Plains states. In Canada, it has been reported only in Ontario. It is
not naturally found in the western Great Plains, southwest, Rocky Moun-
tain region, or the far western Pacific states.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: The flowers offer only pollen as a reward
to insect visitors. Typical floral visitors include various bees, Syrphid flies,
and bee flies; the bees usually collect pollen, while the flies feed on pollen.
Some of these insects explore the showy flowers for nectar in vain. Honey-
bees, little carpenter bees (Ceratina spp.), cuckoo bees (Nomada spp.), ma-
son bees (Osmia spp.), Halictid bees, and Andrenid bees have been observ-
ed as visitors to the flowers. Because the foliage is toxic and relatively in-
conspicuous, it is usually ignored by mammalian herbivores.
The Cherokee used infusions prepared from the roots of rue anemone to
treat diarrhea and vomiting.
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