Pilea pumila (L.) A. Gray
Clearweed is a North American native, a member of the nettle family.
Plants: Clearweed is 6-24" (15-60 cm) high, with smooth, round stems that are somewhat translucent. These plants resemble other nettles, including stinging nettle, but they lack the hairs that cause the sting.
Leaves: 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.
Flowers: Both male and female flowers are found on each plant. Individual flowers are ⅛" (3.2 mm) long, greenish-white or greenish-yellow. They drop in narrow bunches from the axils of the upper leaves.
Fruits: Tiny green seeds (achenes) sometimes have black stripes.
See this article by Steve Brill on distinguishing
among nettles and related plants.
Here are some similar species:
|Plant||24-48" (60-121 cm) high. Stems have stiff white hairs that sting if you rub against them.||4-63" (10-160 cm) high, and favor shady wooded areas. Stems are smooth, without the irritating hairs of stinging nettle.||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.|
|Flowers||Male flower clusters are white or greenish white, in loose branching clusters. Each flower is less than ⅛" (3.2 mm) across, with 5 petals. They appear from July to September.||Flowers occur on straight spikes that emerge from the stem, in clusters of small, inconspicuous green flowers. Each spike is often tipped by a couple of small leaves. Flowers appear from July to August.||Flowers are greenish-tan, and tiny—less than ⅛" (3.2 mm) across. They flower from July to October.|
|Leaves||Alternate, up to 4" (10 cm) × 6" (15 cm), egg-shaped, with coarse serrations.||Usually opposite or nearly so. They are roughly egg-shaped, with sharp tips and teeth. (More precisely, they are elliptic, lanceolate to broadly ovate.) The leaves are 1¾-7" (5-18 cm) × ¾-4" (2-10 cm).||Leaves are alternate, lance-like or oval with sharp tips, 3½" (8.9 cm) × 1" (2.5 cm), with blunt serrations.|
|Fruit||Oblique dry seeds.||Spiky little balls.||A 3-lobed roughly spherical fruit containing 3 seeds.|
|Habitats||Moist woods, streambanks, in rich soils||Moist, deciduous woods; wet meadows; swamps, bogs, and mashes||Open woods, moist soils, gravel bars, waste ground, roadsides, railroads.|
The University of Wisconsin's Robert W. Freckmann Herbarium
Southeastern Flora, the Southeastern U.S. Plant Identification Resource
The Vanderbilt University Bioimages web site
The Lady Bird Johnson Wildflower Center
Newcomb, Lawrence, Morrison, Gordon (Illus.), Newcomb’s Wildflower Guide, Little, Brown and Company, 1977, p. 438
Pilea pumila description by Thomas H. Kent, last updated 16 Sep 2020.