Leonurus japonicus Houtt.

Honeyweed

Leonurus japonicus plant

Family - Lamiaceae

Stem - Erect, to 2 m, 4-angled, finely and retrorsely pubescent.

Leonurus_japonicus_stemStem.

Leaf - Lower leaves broadly ovate, deeply 3-lobed. Upper leaves linear, entire, sharply pointed, with both surfaces finely pubescent.

Leonurus_japonicus_leafLower stem leaf.

Inflorescence - Dense axillary clusters with flowers sessile.

Leonurus_japonicus_inflorescenceInflorescence.

Flowers - Corollas zygomorphic, 10-14 mm long, greatly exceeding calyces, pink, densely and finely pubescent.

Leonurus_japonicus_flowersFlowers.

Fruits - Nutlets 1.5-1.8 mm long, truncate at tip.

Leonurus_japonicus_fruitsInfructescences.

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).



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