Showy tick trefoil

Desmodium canadense, the showy tick-trefoil or Canadian tick-trefoil, is an erect perennial herb in the Fabaceae growing 0.6 to 1.5 meters tall on stout pubescent stems from a woody rootstock. The leaves are pinnately trifoliate, with lanceolate to oblong-lanceolate leaflets 4 to 8 centimeters long that are softly hairy beneath. From July through September the plant produces showy terminal and axillary racemes of bright pink to purple papilionaceous flowers about 1 centimeter long, larger and more conspicuous than in most North American Desmodium species. The fruit is a flat loment of 3 to 5 hairy one-seeded segments densely covered with hooked trichomes that adhere readily to clothing and animal fur, the source of the common name. It grows in moist woods, prairies, stream banks, thickets and roadsides across eastern North America from Nova Scotia and Quebec south to North Carolina and west to North Dakota and Oklahoma, serving as a larval host plant for the eastern tailed-blue and silver-spotted skipper butterflies.