Pilea, genus of 600–715 species of herbaceous creeping plants in the nettle family (Urticaceae) but lacking the stinging hairs typical of that family. The plants are widespread in temperate and tropical regions worldwide. A few are useful as border-edging plants in warm areas, and many varieties are available as indoor pot plants and for hanging baskets.
Especially popular are the artillery plant, or rockweed (Pilea microphylla), with fine fernlike foliage and anthers that forcefully expel their pollen when mature; aluminum plant, or watermelon pilea (P. cadierei), with silvery markings on glossy dark green leaves; Chinese money plant (P. peperomioides), with long petioles (leaf stalks) attached to the centre of the undersides of the round leaves; and friendship plant, or panamiga (P. involucrata), with quilted bronzy leaves.
One of several basket plants called creeping charlie, or Swedish ivy, is P. nummulariifolia, with small, round, quilted leaves and a vigorous trailing habit. Giant baby tears, or depressed clearweed (P. depressa), of similar habit, has small, smooth green leaves.