Common names: nardoo, pepperwort, water clover

Family: Marsileaceae

Could be confused with: Glossostigma, Regnellidium, Trifolium.

Native distribution: Cosmopolitan.

Species commonly cultivated:
Marsilea angustifolia R.Br. (Australia)
M. crenata C. Presl (southeast Asia to Australia)
M. drummondii A. Braun (Australia)
M. exarata A. Braun (Australia)
M. hirsuta R.Br. (Australia)
M. mutica Mett. (Australia)
M. quadrifolia L. (Europe)
M. schelpeana Launert (South Africa)

Adventive distribution: Marsilea quadrifolia was introduced into the northern United States over 100 years ago from Europe. More recently, M. minuta Linn. from Asia, and M .hirsuta and M. mutica from Australia, have become established in Florida.

Weed status: Common weed in rice fields. Marsilea quadrifolia is recognized as a serious weed in rice fields in numerous countries, particularly in Asia.

Habit: Attached, creeping, with submersed, floating and emergent leaves.

Brief description: Perennial water fern. Rhizome creeping or floating, rooted at nodes. Fronds (leaves) scattered along rhizome, submersed, floating or emergent; long, upright petiole terminating in a divided blade of 4 leaflets that appear like a four-leaf clover, rarely 1-lobed; leaflets smooth or hairy, venation palmate; margins entire or crenate. Sporocarps closed, axillary, on short stalks, solitary or clustered at base, ovoid, hairy or glabrous.

Natural habitat: Shallow, marginal waters and littoral zone of lakes, rivers, ponds swamps, etc.; also wet ground; will tolerate drying out for extended periods as a resting stage.

Additional comments: Marsilea contains 60-70 species worldwide, with several grown in aquaria or ponds. A species of Marsilea (most likely M. angustifolia) from Australia is present in the aquarium trade and is exceptional because of the preponderance of single lobed leaves on a short petiole when grown submersed.