Soleirolia soleirolii

Soleirolia soleirolii is a creeping perennial from the shaded rock crevices and damp walls of the western Mediterranean — Corsica, Sardinia, Elba, and the Balearic Islands — where it forms soft mats of tiny round leaves no more than a few millimetres across. Despite belonging to the nettle family (Urticaceae), it has no sting; the threadlike stems root at every node as they spread, so a single sprig can carpet a substrate within months. Its many common names — Baby's Tears, Angel's Tears, Mind-Your-Own-Business, Paddy's Wig — all describe the same dense green cushion. In a terrarium it does best in steady high humidity with bright indirect light, but the closed-jar setting needs some airflow: without it the lower stems mat down and rot, and the plant will smother slower-growing neighbours if left unchecked.