Marsilea mutica
Common name
nardoo
Family
Marsileaceae
Flora category
Vascular – Exotic
Structural class
Ferns
Conservation status
Not applicable
Brief description
A perennial fern with slender, rooted branching rhizomes and erect leaves (sterile fronds) along their length. The mature leaf resemble a four leaf clover and consists of four oblanceolate to egg/wedge shaped, glabrous to hairy leaflets at the apex of a slender stalk; leaflets are held more or less horizontially, or they may fold up on one another, each with numerous, fine, close-set longitudinal veins. The young developing leaves near the rhizome are filiform with coiled tips (fern like). Sporocarps are mostly produced by plants growing on drying mud, and rarely on those in the water.
Distribution
Introduced and Naturalised. New Zealand: North Island (farm ponds at Hunua (South Auckland) and Paraparaumu (Wellington) and ornamental ponds elsewhere). Indigenous to Australia and New Caledonia.
Habitat
Plants are either aquatic or on mud, mostly in areas subject to at least temporary inundation. When the plants are growing in the water they have floating leaflets.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Detailed description
Characterised by floating, clover like-fronds with four leaflets, can also be emergent from shallow water. Rhizome is glabrous, although there are a few hairs at the nodes that bear roots. Leaves are solitary and occur at intervals along the rhizome. Leaf stalks are 5–25 cm long in terrestrial forms, but may be longer in aquatic forms, up to 90 cm. Leaflets are mostly green, but also yellowish in the centre and have a brown demarcation line at the leaflet margin. The leaflets, four together, are smaller in terrestrial forms (1–5 cm) and c. 4–8 cm diameter in aquatic forms. Sporocarps occur most frequently in 2–4 on a branched pedicel, which arises from the base of the leaf-stalk or on short branches that are attached to the leaf stalk a few millimetres from its base.
Flower colours
No flowers
Life cycle
Vegetative fragments and by spores.
Year naturalised
1988
Origin
Native to Australia and New Caledonia
Reason for introduction
Ornamental pond plant
Attribution
Prepared by Paul Champion and Deborah Hofstra (NIWA)
References and further reading
Johnson PN, Brooke PA. 1989. Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington, NZ. 319 p.
Aston H. 1977. Aquatic plants of Australia. Melbourne University Press, Melbourne, AUS. 367 p.