Water clover (several species)

Description

Marsilea species, aquatic ferns with over 40 species worldwide, are popular foreground plants in aquarium hobby. They grow on thin rhizomes and have leaves divided into four parts with long stalks, resembling four-leaf clover. The plants can be found in almost all continents and several species are offered in trade, mainly M. crenata and M. hirsuta. However, identification can be challenging without the sporocarps which only develop on emersed forms. Submersed forms usually have similar growth habits and appearances. Marsilea species are undemanding and do well under moderate light and regular nutrients. Stronger light and CO2 injection promote stronger growth. Planting involves placing 2-5 cm long rhizome pieces into the substrate at regular distances, which can be propagated by new rhizomes and leaves forming on the planted pieces. Emersed cultivation requires moist to wet substrate and may need longer acclimation time, while submersed plants should have their long-stalked floating leaves cut off several times to stop development. In shallow water or outdoor containers, Marsilea can form typical four-leaf-clover leaves. They are popular ground covers in aquascapes and can grow long leaf stalks under insufficient light, which can be cut off.