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artillery plant, artillery weed, pistol plant, rockweed

artillery plant

Habit Herbs, annual or short-lived perennial, 0.3-2 dm. Shrubs or subshrubs, 1.5-5 dm.

10-40-branched, erect.

10-30-branched, erect or diffusely ascending.


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 with members of pair unequal, the larger obovate, 5-10 × 4-6 mm, the smaller nearly orbiculate to orbiculate-cordate, 2-5 mm wide, margins entire.





ca. 0.5 mm across.

ca. 0.3-0.5 mm across.


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

uniformly light brown, slightly compressed, ovoid-cylindric, ca. 0.7 × 0.5 mm, pebbled.

Pilea microphylla

Pilea trianthemoides

Phenology Flowering all year. Flowering all year.
Habitat Waste places, hammocks, rocky woods, cultivated plots, on masonry Waste places, moist thickets, persisting after cultivation
Elevation 0-100 m (0-300 ft) 0-20 m (0-100 ft)
from FNA
FL; GA; LA; SC; HI; Mexico; Central America; West Indies; tropical South America; Asia
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from FNA
FL; West Indies [Introduced in North America]
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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.)

The group including Pilea microphylla and P. trianthemoides is in need of taxonomic study. Although in the United States these two species generally can be separated without difficulty, in the West Indies they appear to intergrade. In the West Indies, P. trianthemoides is sometimes treated as P. microphylla var. trianthemoides (Swartz) Grisebach.

The name Pilea serpyllifolia (Poiret) Weddell was misapplied to this taxon by J. K. Small.

(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. pumila
Synonyms Parietaria microphylla Urtica trianthemoides
Name authority (Linnaeus) Liebmann: Naturvidensk. Math. Afd., ser. 5, 2: 296. (1851) (Swartz) Lindley: Coll. Bot., plate 4 and text on facing page. (1821)
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