Desmodium canadense
Margaret Melgaard,
Wisconsin State Herbarium Emmet J. Judziewicz,
Wisconsin State Herbarium Showy Tick Trefoil is a
common wildflower with small pink flowers. It grows up to
six feet tall, but is usually much shorter. This plant blooms in July
and August with large clusters of flowers, but it is
probably best known for its seeds, which cling to people's
socks and clothing. Showy Tick Trefoil grows
in fields, meadows, roadsides, shores, open woods, and
edges. Emmet J. Judziewicz,
Wisconsin State Herbarium Stan Malcom The leaves of Showy Tick
Trefoil are split into three leaflets. Leaflets are usually
dark green and slender, growing up to three inches
long. Each pink (sometimes
purple) flower is only 1/2 inch long, but they are always
together in long clusters. Flowers have two petals which are
important in pollination. This plant has a special
way to make sure it gets pollinated. When an insect, such as
a bee or butterfly, lands on a flower to collect nectar, the
two petals close on the insect and the flower shoots pollen
on its body. The flower then relaxes and the insect is free
to visit elsewhere. Once a flower has been
pollinated (received pollen from another flower), it dies
and a fruit takes its place. The fruits of Showy Tick
Trefoil are hairy pods, split into triangle-shaped seeds.
When an animal brushes against the plant, the hairs on the
seed grab onto its fur. This way the seeds can travel to new
places and grow new plants. As the plant grows older,
it leans over closer to the ground. This makes sure animals
will be able to rub agains it. Showy Tick Trefoil seeds
grow quickly after fires. This plant is also perennial,
meaning it grows back every year. Showy Tick Trefoil is a
host plant for the caterpillars of many butterfly species,
including Silver-spotted Skipper, Clouded Sulphur, and
Eastern Tailed Blue. Small adult butterflies
visit trefoil flowers for nectar, especially hairstreaks and
coppers (two families of small butterflies). Bees also visit
flowers for nectar and, as mentioned above, all of these
insects help pollinate the flowers. The seeds of Showy Tick
Trefoil are eaten by Northern Bobwhite, Wild Turkey, Eastern
Towhee, Dark-eyed Junco, Virginia Opossum, and White-footed
Mouse. White-tailed Deer eat
leaves and stems. Showy Tick Trefoil is
helped by a bacteria called Rhizobium. Stan Malcom
