Marsilea

Scientific name

Marsilea L.

Common names

nardoo, pepperwort, water clover

Family

Marsileaceae

Similar genera

Glossostigma, Menyanthes, Oxalis, Regnellidium

Native distribution

cosmopolitancosmopolitan:
(adj) essentially worldwide in distribution

Species cultivated

numerous species worldwide; some examples include:

Marsilea angustifolia R.Br.

M. crenata C. Presl

M. drummondii A. Braun

M. exarata A. Braun

M. hirsuta R.Br.

M. mutica Mett.

M. quadrifolia L.

M. schelpeana Launert

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. M. crenata and M. drummondii have been introduced into the United States also.

Weed status

A common weed in rice fields; Marsilea quadrifolia L. is recognized as a serious weed in rice fields in numerous countries.

Habit

attached, creeping, with submersedsubmersed:
see submerged
, floating, and emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
leaves

Brief description

Perennial perennial:
(adj) (of a plant) having a life cycle of more than two years
water fern. Rhizomerhizome:
(n) an underground stem, usually growing horizontally, from which both roots and shoots emerge directly; the thick, above-ground stem of ferns
creeping or floating, rooted at nodes. Fronds (leaves) scattered along rhizomerhizome:
(n) an underground stem, usually growing horizontally, from which both roots and shoots emerge directly; the thick, above-ground stem of ferns
, submersedsubmersed:
see submerged
, floating or emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
; long, upright petiolepetiole:
(n) the stalk of a leaf
terminating in a divided bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
of 4 leaflets that appear like a four-leaf clover, rarely 1-lobed; leaflets smooth or hairy, venationvenation:
(n) the arrangement of veins in a leaf
palmatepalmate:
(adj) (of leaves or venation) with lobes, leaflets, divisions or veins originating from the same point
; margins entireentire:
(adj) having a continuous margin that is not toothed or lobed
or crenatecrenate:
(adj) (of a margin) with shallow, rounded teeth
. Sporocarps closed, axillaryaxillary:
(adj) in, of, or produced from an axil
, on short stalks, solitary or clustered at base, ovoidovoid:
(adj) egg-shaped in three dimensions
, hairy or glabrousglabrous:
(adj) without hairs or scales
.

Natural habitat

shallow, marginal waters and littorallittoral:
(adj) of or along the shore
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 27 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 lobedlobed:
(adj) divided into (usually rounded) segments
leaves on a short petiolepetiole:
(n) the stalk of a leaf
when grown submersedsubmersed:
see submerged
.