• Hardiness: Easy
  
• Light Needs: Medium
  
• Plant Structure: Moss / Fern
  
• Family: Marsileaceae
  
• Genus: Marsilea
  
• Region: Cosmopolitan
  
• Location: Cosmopolitan
  
• Size: 1/8-1-2 inch leaf width, 1/4-1 inch tall submersed growth
  
• Growth Rate: Moderate
  
• Can Be Grown Emersed: Yes
  

The various species of Marsilea have collectively become some of the most popular plants for the foreground in the hobby. Their ease of growth and steady propagation make them more popular than the similarly-leaved Glossostigma elatinoides. Technically ferns, there are over forty species identified, and their distribution is cosmopolitan, with species found in Europe, Asia, Africa, North America and Australia. Several are available in the hobby. However, differentiating between them is problematic without having the sexual reproductive structures, called sporocarps, which are formed in emersed conditions only. The growth patterns and appearance of the species widespread in aquariums are similar enough that determining the exact species is often not of great importance. Species commonly seen include M. crenata, M. hirsuta, M. quadrifolia, M. mutica and M. minuta. Less common are M. drummondii and M. angustifolia. The easiest species to differentiate in this group is M. minuta. With lush nutrients and high light, its leaves will be much smaller than those of the other species available. However, under more modest conditions, its appearance can be similar to the rest.

Marsilea species are relatively undemanding and can be grown in moderate lighting with a regular fertilizing regimen. Higher lighting and carbon dioxide injection improve growth rate and promote more compact growth.

Emersed growth is possible in very moist soil; plants also grow as rooted floating plants in shallow water, where many of them are used in ponds. In both situations, these plants grow four-lobed leaves similar to those of four-leaf clovers. Indeed, plants of Marsilea quadrifolia have been used as a substitute for four-leaf clovers for Saint Patrick's Day celebrations in the past.

The various Marsilea species are planted by taking one to two-inch sections of rhizome and planting them in the substrate at regular intervals. Propagation is straightforward, as new rhizomes and leaves form from the planted sections. There is often an extended adaptation period for submersed-grown stock, but once the plants are established, growth is steady. Any leaves on plants that have grown completely emersed or floating should be removed; new leaves of the latter formed after planting should be clipped. After a short time, no more will be produced.

This group of plants has become quite popular as foreground cover in various types of aquascapes. Shaded areas or inadequate lighting promote the growth of taller and two, three or four-lobed leaves. These can be easily trimmed at the aquascaper’s discretion. Maintenance involves thinning out the mat of plants as they become too thick. This can be accomplished by carefully pulling up groups of runners and trimming. Alternatively, complete sections may be removed and then replanted. Creating a slope with the substrate prior to planting provides more sense of depth when using Marsilea species.

Given their current popularity, the various Marsilea species can be easily obtained from other hobbyists, nurseries and retailers. M. quadrifolia can also be obtained in many aquarium and pet stores in its emersed form.