Canada clearweed
(Pilea pumila)
Conservation • Wetland • Description • Habitat • Ecology • Use • Distribution • Taxonomy
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Description |
Canada clearweed is a 4″ to 20″ tall, erect, annual forb that rises on a single stem from fibrous, shallow, adventitious roots. It often forms large colonies. The stems are erect, light green grayish-green, or reddish-green, transparent, unbranched, smooth, and hairless. The are round in cross section. The leaves are opposite, thin, elliptic to broadly elliptic or egg-shaped, 1¼″ to 5″ long, and ⅜″ to 3½″ wide. They are on leaf stalks that are often 1″ long or longer. Each leaf is equal in size to the leaf on the opposite side of the stem. The leaf blade is broadly wedge-shaped or rounded at the base. It does not have ear-like lobes at the base. It is slightly transparent, most noticeably on the lower surface. The margins are coarsely toothed with sharp or rounded, forward-pointing teeth. The tooth at the tip is elongated. The upper surface is medium to dark green, shiny, and hairless. The lower surface is light green and hairless. There are three parallel main veins, the midvein and two lateral veins that arch toward the tip. The veins are conspicuously depressed on the upper surface, giving the leaf blade a quilted or wrinkled appearance. The leaves turn bright yellow in the fall. The inflorescence is a crowded or loose, ¼″ to 1¼″ long, branched, flat-topped cluster (cyme) rising from the upper leaf axils. The cyme is 55% to 70% as long as wide and shorter than the leaf stalk. It contains both male and female flowers. The flowers are less than ⅛″ long and about 1 ⁄32″ in diameter. Male flowers have no petals, 4 greenish-white sepals, and 4 stamens. Female flowers have no petals, 3 greenish-white sepals, and 1 style. The flowers are not fragrant. The fruit is a dry, tear-drop shaped, 1 ⁄32″ to 6 ⁄16″ long seed case (achene). It is green or greenish-yellow at maturity, sometimes with fine, purple lines. The purple lines, when present, are sometimes slightly raised. |
Height |
4″ to 20″ |
Flower Color |
Greenish-white |
Similar Species |
Stinging nettle (Urtica dioica ssp. gracilis) is a much taller plant, up to 72″ in height. The stem and leaves have stinging hairs. |
Habitat |
Moist to wet. Woodlands, woodland margins, and streambanks. Full shade. In rich soil. |
Ecology |
Flowering |
July to September |
Pests and Diseases |
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Use |
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Distribution |
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Sources |
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| 10/9/2024 | ||
Nativity |
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Native |
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Occurrence |
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Common |
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Taxonomy |
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Kingdom |
Plantae (green algae and land plants) |
Subkingdom |
Viridiplantae (green plants) |
Infrakingdom |
Streptophyta (land plants and green algae) |
Superdivision |
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Division |
Tracheophyta (vascular plants) |
Subdivision |
Spermatophytina (seed plants) / Angiospermae (flowering plants) |
Class |
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Superorder |
Rosanae |
Order |
Rosales (roses, elms, figs, and allies) |
Family |
Urticaceae (nettle) |
Genus |
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Some botanists recognize the variety Pilea pumila var. deamii. It has denser sharper teeth and narrowly angled leaf bases. GBIF and USDA Plants recognize the the variety. Most other sources do not, including ITIS, GRIN, Flora of North America, World Flora Online, and Plants of the World Online. Two varieties are recognized in China. When only a single variety or subspecies (subtaxa) occurs in North America, it is customary for North American sources to use only the genus and species (binomial name), omitting the subtaxa name. |
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Subordinate Taxa |
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Synonyms |
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Adenia pumila Adicea glabra Adicea mongolica Adicea pumila Adicea trinervia Adike pumila Dubrueilia pumila Pilea mongolica Pilea pumila ssp. pumila Pilea pumila var. deamii Pilea pumila var. pumila Pilea viridissima Urtica fasciculata Urtica pumila |
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Common Names |
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Canada clearweed Canadian clearweed clearweed coolwort dwarf clearweed greenfruit clearweed richweed |
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Glossary
Achene
A dry, one-chambered, single-seeded seed capsule, formed from a single carpel, with the seed attached to the membranous outer layer (wall) only by the seed stalk; the wall, formed entirely from the wall of the superior ovary, does not split open at maturity, but relies on decay or predation to release the contents.
Adventitious roots
Roots originating on any part of the plant other than the usual underground root zone: the lower stem above ground, the branches, or the leaves.
Axil
The upper angle where the leaf stalk meets the stem.
Cyme
A branched, flat-topped or convex flower cluster in which the terminal flower opens first and the outermost flowers open last.
Sepal
An outer floral leaf, usually green but sometimes colored, at the base of a flower.
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Greg Watson |
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Canada Clearweed, Pilea pumila ¬– you don’t have a picture of this plant. |
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Other Videos |
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Identifying and Removing Clearweed |
About
Uploaded on Jan 14, 2010 Dave shows you how to identify and remove clearweed. |
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| Greg Watson 9/24/2024 |
Location: Norwegian Ridge Birding and Nature Trails Canada Clearweed, Pilea pumila ¬– you don’t have a picture of this plant. |
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