Parietaria pensylvanica
Family: Urticaceae
Description: Annual to 30 cm or higher with mostly alternate, lanceolate leaves 0.5-6 cm long. Herb with juicy stem, erect when young, leaning or prostrate when older, with curved or hooked hairs. Leaves alternate, blades lanceolate, up to 5 cm long with pointed tips; margins smooth or slightly undulate. Flowers are tiny, greenish, in lusters in the leaf axils. Flowers in axillary clusters, polygamous. Perianth 1-2 mm long, green or whitish.
Field Identification: Stems are 4-angled, green, often pubescent.
Plant Trivia: The genus name comes from the Greek parietarius (“wall”), reflecting its common growth in wall crevices and other cracks. Wind-pollinated. Self-seeding, often forming colonies.
Occurrence: Frequent on various soils in pastures and woods, usually shaded. Dry ledges, rocky slopes, calcareous cliffs, barrens, rich floodplains, mesic woodlands, savannas, thickets, fence rows, stone walls, and disturbed areas. This is a native annual herb in the nettle family (Urticaceae) found widely across North America.
Bloom Period: Jan-June
Plant Use:
Dichotomous Key to the two species of Urticaceae:
- Leaves alternate………………….Parietaria
Leaves opposite…………………….Urtica
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