Pilea nummulariifolia

Pilea nummulariifolia is a creeping herb of moist, shaded ground from Central America and the Caribbean to Venezuela, Colombia, Ecuador and Peru, where its runners put down roots at every node as they spread. Its round to oval leaves, usually 1–2.5 cm across, are deeply scalloped and softly hairy, with sunken veins that give the surface a quilted, crinkled look — the species name refers to their coin-like shape, and it is unrelated to the lawn weed ground ivy, which shares the name creeping Charlie. The pinkish-brown stems grow 10–50 cm long and quickly knit into a dense mat or spill from a hanging basket; outside its native range it has naturalised in Hawaii, Bermuda and Taiwan. In a terrarium it makes a fast, forgiving ground cover that needs regular trimming to stay off its neighbours, and it does best in bright indirect light with steady moisture and humidity, since it does not tolerate drying out.