Acalypha rhomboidea (Three-seeded Mercury)
|Also known as:||Rhombic Copperleaf|
|Habitat:||part shade, sun; disturbed soil, waste places|
|Bloom season:||June - October|
|Plant height:||8 to 24 inches|
|Wetland Indicator Status:||GP: FACU MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Tiny petal-less flowers form in dense clusters of palmately lobed, leafy bracts at the leaf axils, with separate male and female flowers. The yellowish to brown male (staminate) flowers are on a short stalk with 2 to 3 green female (pistillate) flowers at the base of the stalk in the center of bract. The lobes of the bracts are irregular, lance-like with pointed tips. ranging in color from light green to deep coppery-red and may be smooth but often with scattered hairs, especially along the edges and undersides.
Leaves and stems:
Leaves are 1 to 4 inches long, up to 1 inch wide, mostly oval to lance-like tending towards rhombic angles, sparsely hairy, with long slender stalks that can be more than half as long as the leaf blade. The edges are serrated with shallow, blunt teeth. Leaves may appear almost whorled at the end of the stem but they are merely tightly packed, alternately attached. Leaves are typically medium to dark green but the plant can become deep coppery red, especially the stems, bracts and undersides of leaves. Stems are erect, hairless or somewhat hairy, mostly unbranched with the occasional short flowering side branches.
Three-seeded Mercury is a common native of abandoned lots, roadsides, railroads, and disturbed soil. A number of plants volunteered in my own backyard garden. It is generally considered a weedy species, but does not take over areas like invasive species do. Pennsylvania Pellitory (Parietaria pensylvanica) is similar in structure, but is a smaller plant with toothless leaves.
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Photos courtesy Peter M. Dziuk taken in Anoka County.
Have you seen this plant in Minnesota, or have any other comments about it?