Leonurus japonicus Houtt.
Family - Lamiaceae
Stem - Erect, to 2 m, 4-angled, finely and retrorsely pubescent.
Leaf - Lower leaves broadly ovate, deeply 3-lobed. Upper leaves linear, entire, sharply pointed, with both surfaces finely pubescent.
Lower stem leaf.
Inflorescence - Dense axillary clusters with flowers sessile.
Flowers - Corollas zygomorphic, 10-14 mm long, greatly exceeding calyces, pink, densely and finely pubescent.
Fruits - Nutlets 1.5-1.8 mm long, truncate at tip.
Flowering - July - August.
Habitat - Barnyards, roadsides, disturbed areas.
Origin - Native to Eurasia.
This is a rare plant in Missouri, having been found in only two counties so far. The plant was first collected in Missouri in 1990 by Father James Sullivan, who sampled a population in Weldon Spring which had been known locally for a decade or more. The population was still present as of 2018, and appeared to be very slowly expanding in extent.
Photographs taken in Weldon Spring Conservation Area, 8-30-2009, 10-21-2009, and 8-15-2011 (SRTurner).