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artillery plant, artillery weed, pistol plant, rockweed

Canada clearweed, Canadian clearweed, clearweed

Habit Herbs, annual or short-lived perennial, 0.3-2 dm. Herbs, 0.7-7 dm.

10-40-branched, erect.

simple, erect.


blades spatulate to obovate, paired blades unequal, the larger 3-10 × 1.5-5.5 mm, the smaller 1.5-4 × 0.7-2 mm, margins entire.

blades elliptic to broadly elliptic or ovate, paired blades equal, 2-13 × 1-9 cm, margins dentate.



crowded to lax.


ca. 0.5 mm across.

ca. 1 mm across.


uniformly light brown, slightly compressed, ovoid-cylindric, ca. 0.5(-1.1) × 0.3 mm, smooth.

uniformly light colored or with streaks of purple, compressed, teardrop-shaped, 1.3-1.7 × 0.6-1.1 mm, smooth or purple striations sometimes raised.


= 24, 26.

Pilea microphylla

Pilea pumila

Phenology Flowering all year. Flowering summer–fall.
Habitat Waste places, hammocks, rocky woods, cultivated plots, on masonry Moist to wet woods, woodland margins, along streams, shaded waste places
Elevation 0-100 m (0-300 ft) 0-2000 m (0-6600 ft)
from FNA
FL; GA; LA; SC; HI; Mexico; Central America; West Indies; tropical South America; Asia
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from FNA
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; NB; ON; PE; QC; Asia
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Pilea microphylla has been collected once in Tennessee and once in Michigan, but it is unlikely that the species persists so far north. It is widely grown as a houseplant in the north and a border plant in the south. It is a greenhouse weed in various parts of the flora.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Typical plants have leaf blades with cuneate bases and 3-11 rounded teeth on each margin; plants with rounded leaf bases and 11-17 less rounded or acute teeth on each margin have been called Pilea pumila var. deamii (Lunell) Fernald (M. L. Fernald 1936) [Adicea deamii Lunell, Amer. Midl. Naturalist 3: 10. 1913.]. Typical P. pumila also is found in eastern Asia, where three infraspecific taxa, P. pumila var. pumila, P. pumila var. hamaoi (Makino) C. J. Chen, and P. pumila var. obtusifolia C. J. Chen are recognized. This complex, which also includes P. pauciflora C. J. Chen, has been placed in Pilea series Pumilae C. J. Chen. Although the Asian plants are often vegetatively and florally indistinguishable from the North American plants, minor differences do occur in the achenes, especially in their markings and sculpturing when mature. Detailed studies are needed to clarify exact relationships.

Native Americans used Pilea pumila medicinally to alleviate itching, to cure sinus problems, and to treat excessive hunger (D. E. Moerman 1986)

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 3. FNA vol. 3.
Parent taxa Urticaceae > Pilea Urticaceae > Pilea
Sibling taxa
P. fontana, P. herniarioides, P. pumila, P. trianthemoides
P. fontana, P. herniarioides, P. microphylla, P. trianthemoides
Synonyms Parietaria microphylla Urtica pumila
Name authority (Linnaeus) Liebmann: Naturvidensk. Math. Afd., ser. 5, 2: 296. (1851) (Linnaeus) A. Gray: Manual, 437. (1848)
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