Acalypha rhomboidea (Three-seeded Mercury)

Acalypha rhomboidea

Acalypha rhomboidea Raf.

Acalypha virginica L. var. rhomboidea (Raf.) Cooperr.

Three-seeded Mercury, Rhombic Three-seeded Mercury, Rhomboid Mercury, Rhombic Copperleaf

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Rosidae	Roses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more
Order	Malpighiales	A broad group encompassing 16,000 species
Family	Euphorbiaceae	Euphorbia or spurge family
Genus	Acalypha	Copperleaves or three-seeded mercuries; means “nettle”
Species	rhomboidea	“Diamond-shaped” leaves

About plant names...

Three-seeded mercury is a member of the highly variable Euphorbia family. The genus, Acalypha, is from the Greek akalyphē, meaning “nettle,” because these plants resemble nettles. The species rhomboidea refers to the rhomboid shape of the leaves. Three-seeded mercury refers to the fruits—capsules with three seeds. I have no clue where “mercury” comes from though.

Identification: Plants are 6-24" (15-60 cm) tall, with a stem that is hairless or covered with fine white hairs. Leaves are alternate, lance-like or oval with sharp tips, 3½" (8.9 cm) × 1" (2.5 cm), with blunt serrations. Flowers are greenish-tan, and tiny—less than ⅛" (3.2 mm) across. Although the flowers are inconspicuous, the bracts (modified leaves) surrounding them turn copper-colored, along with the stems and leaf undersides, hence the common name “copperleaf.” They flower from July to October. See this article by Steve Brill on distinguishing among nettles and related plants.

9/27/2010 · Nashua River Rail Trail, Groton, MA
≈ 7 × 11" (18 × 27 cm) ID is uncertain

9/1/2013 · Trail Near James River, Midlothian, VA
≈ 5 × 8" (12 × 19 cm)

Here are some similar species:

	*Laportea canadensis*	You are here Acalypha rhomboidea	*Pilea pumila*
Common Name	Wood Nettle	Three-seeded Mercury	Clearweed
Plant	24-48" (60-121 cm) high. Stems have *stiff white hairs that sting* if you rub against them.	6-24" (15-60 cm) tall, with a stem that is *hairless or covered with fine white hairs. Bracts beneath flowers, stems, and leaf undersides turn copper-colored*.	6-24" (15-60 cm) high, with smooth, round, translucent stems. They *do not have stinging hairs*.
Flowers	Greenish-white, appearing from July to September.	Flowers are greenish-tan, and tiny—less than ⅛" (3.2 mm) across. They flower from July to October.	Both male and female flowers are on each plant. Fowers are ⅛" (3.2 mm) long, greenish-white or greenish-yellow, hanging in narrow bunches from the axils of the upper leaves.
Leaves	Alternating, up to 4" (10 cm) × 6" (15 cm), egg-shaped, with coarse serrations.	Leaves are alternate, lance-like or oval with sharp tips, 3½" (8.9 cm) × 1" (2.5 cm), with blunt serrations.	Leaves occur in opposite pairs, each 1-5" (2.5-12 cm) long by ½-2½" (1.3-6.3 cm) wide. Leaves are oval-shaped and coarse-toothed, with three prominent veins and textured leaves. The leaves are bright green, usually shiny, and become yellow in the fall.
Range/ Zones
Habitats	Moist woods, streambanks.	Open woods, moist soils, gravel bars, waste ground, roadsides, railroads.	Wet upland or floodplain forests, crevices in rocky canyons, and shady wetlands, streambanks.
Type	Wild	Wild	Wild

Online References:

Acalypha rhomboidea on Missouriplants.com

Acalypha rhomboidea at Minnesota Wildflowers

Acalypha rhomboidea at Illinois Wildflowers

Acalypha rhomboidea on Southeastern Flora, the Southeastern U.S. Plant Identification Resource

Acalypha rhomboidea at the University of Wisconsin's Robert W. Freckmann Herbarium

Acalypha rhomboidea at the Lady Bird Johnson Wildflower Center

References:

Newcomb, Lawrence, Morrison, Gordon (Illus.), Newcomb’s Wildflower Guide, Little, Brown and Company, 1977, p. 416

9/27/2010 · Nashua River Rail Trail, Groton, MA
≈ 4 × 6" (10 × 15 cm) ID is uncertain

9/1/2013 · Trail Near James River, Midlothian, VA
≈ 7 × 4½" (18 × 12 cm)

8/18/2012 · Nashua River Rail Trail, Groton, MA
≈ 4½ × 7" (11 × 17 cm) ID is uncertain

8/18/2012 · Nashua River Rail Trail, Groton, MA
≈ 4 × 6" (10 × 15 cm) ID is uncertain

8/18/2012 · Nashua River Rail Trail, Groton, MA
≈ 3½ × 5" (9.2 × 13 cm) ID is uncertain

Acalypha rhomboidea description by Thomas H. Kent, last updated 25 Dec 2018.

9/1/2013 · Trail Near James River, Midlothian, VA
≈ 4½ × 6" (12 × 16 cm)

8/7/2010 · Tom and Susan’s, Pepperell, MA
≈ 3½ × 4½" (9.4 × 11 cm) ID is uncertain

8/18/2012 · Nashua River Rail Trail, Groton, MA
≈ 4½ × 7" (11 × 17 cm) ID is uncertain

9/1/2013 · Trail Near James River, Midlothian, VA
≈ 6 × 8" (14 × 20 cm)

9/27/2010 · Nashua River Rail Trail, Groton, MA
≈ 8 × 12" (20 × 31 cm) ID is uncertain

Range:

About this map...