1-2-Grow! Marsilea minuta

Previously known as Marsilea crenata. This small fern comes from Asia, where it often grows in rice fields. The leaves are tiny and rarely wider than 0.5cm. 
It is a hardy plant that tolerates poor light conditions and high temperatures. However, improved conditions are beneficial to the plant. Planted in small bundles that spread with offshoots. Creates a 1-3cm high and close carpet, well-anchored in the bottom layer.