This herbaceous perennial plant is 1-4' tall and usually unbranched,
except sometimes at the base. The central stem is light green,
short-pubescent, and 4-angled with shallow vertical grooves. At
intervals, there occurs pairs of opposite leaves that become slightly
shorter and more narrow as they ascend the stem. Each pair of leaves
rotates about 90° from the pair of leaves either immediately above or
below. The leaf blades are 1-3" long, 1/3-1¼" (8-31 mm.) across, and flat; they
are ovate to oblong-lanceolate in shape and their margins are dentate
to sparsely crenate. The upper surface of each leaf blade is medium
green and sparsely short-pubescent, while the lower surface is slightly
more pale and pubescent (at least along the central veins). On each
leaf blade, there are usually 2 lateral veins that run parallel to the
central central and a few secondary veins that branch from the
central vein along its length. The petioles of the leaves are ¼-¾"
long. The lowest leaves, which are wider, are often withered by the
time that flowering occurs.
The flowers occur in dense axillary
clusters along the upper half of each stem; these floral clusters are
whorled and sessile. Individual flowers are about ¼" (6 mm.) long and 1/8" (3 mm.)
across, consisting of a 2-lipped tubular corolla with 4 lobes, a
calyx with 5 teeth that have spine-like tips, 4 stamens, and a
pistil with an ovary that is divided into 4 parts. The corolla is white
to pink and softly short-hairy along the exterior of the upper lobe,
which functions as a protective hood. There is also a rounded lower
lobe and two smaller lateral lobes. A patch of red occurs within the
throat of the corolla. The calyx is light green, sparsely canescent
along its exterior, and 5-veined. The corolla of the flower is about
the same length as the calyx (including the tips of its teeth) or
a little longer. The blooming period occurs from early summer to early
fall for about 2-3 months. Usually, only a few flowers are in bloom at
the same time across several floral clusters. Each flower is replaced
by a cluster of 4 small nutlets during the
fall. Individual nutlets are
oblongoid and 3-sided. The root system is fibrous and rhizomatous.
Clonal colonies of plants are often formed from the rhizomes.
The preference is full sun to light shade, moist to dry-mesic
conditions, and loamy, rocky, or sandy soil that is calcareous.
Depending on fertility of the soil, moisture levels, and time of
year, individual plants can vary considerably in their height.
False Motherwort is uncommon to
central and NE Illinois, while in the rest of the state it is rare or
absent. This plant is not native to Illinois; it
was accidentally introduced into North America from Eurasia. Habitats
include dolomite prairies, sandy savannas near Lake Michigan,
riverbanks, roadsides, and pastures. This plant is usually found in
disturbed areas, although it sometimes occurs in higher quality
Very little is known about
floral-faunal relationships for this plant in North America, although
they are probably similar to those for Motherwort (Leonurus cardiaca
which is closely related to False Motherwort and more common. The
flowers are likely pollinated by various bees, including bumblebees,
little carpenter bees (Ceratina
.), and Halictid bees (Halictus
), which seek nectar or collect pollen from the
flowers. Syrphid flies may also visit the flowers to feed on pollen,
but they are less effective at cross-pollination. The Currant Aphid
uses Leonurus spp.
(Motherworts) as summer hosts. Because of the
bitter foliage, it is unlikely that mammalian herbivores browse on
False Motherwort to any significant extent.
A sandy oak savanna near Lake Michigan at the
Indiana Dunes State Park in NW Indiana.
Across different populations, the leaf blades of False Motherwort can
vary significantly in their width and in the abundance or size of the
teeth along their margins. This plant is sometimes referred to as
but it differs from Leonurus
by the lack of cleft lobes on its leaves. Like Motherwort (Leonurus
), False Motherwort can be distinguished from many
other members of the Mint family by the spiny teeth of its calyces, the
shape of its leaves, and other characteristics. Other common names of
this plant are Lion's Tail and Horehound Motherwort.