Taxon Attribute Profiles

Fronds floating on water surface.

Marsilea drummondii A.Braun

Common Nardoo

Introduction

Marsilea drummondii is a common and widespread fern of wetland areas across inland Australia. It grows from a creeping rhizome, reproducing from sporocarps, and can form dense swards following flooding so that it is the dominant component of the groundcover layer.

Taxonomy and Ecology

Classification

Family: Marsileaceae

Genus: Marsilea - approximately 65 species worldwide; c. 6 species in Australia.

Notes: For a recent taxonomic description of Marsilea drummondii see Jones (1988).

Upright fronds, slightly hairy, with sporocarps on short stems at their base.

Life form

Marsilea drummondii is an aquatic perennial rhizomatous fern. It is highly polymorphic in many features. The sterile fronds are erect when growing in mud, floating when growing in water (Jones, 1998), each consisting of two pairs of leaflets arranged in a fourleaf-clover pattern. The flexible stems allow the plants to adapt to small changes in water level (although M. drummondii has been seen in water up to 1 m deep), while keeping their leaves on the water surface to access light and carbon dioxide (Roberts and Marston, 2000).

Floating (left) and emerging with upright fronds (right) on the edge of a pool.

click to enlarge map

Distribution

Marsilea drummondii is endemic to inland areas of Australia (Jones, 1998), occurring in all states and territories except Tasmania and the Australian Capital Territory.

Habitat

Marsilea drummondii grows in shallow, still or sluggishly flowing water, in seasonally wet habitats (Jones, 1998) such as on the margins of gilgais, waterholes, claypans, swamps, rivers and their floodplains, roadside table-drains and depressions in many vegetation communities (Cunningham et al., 1981). It has also been observed in flowing floodwaters to 1 metre deep (Roberts and Marston, 2000), and commonly persists in drying mud (pers. comm., D.L. Jones, 2004) and marshy sites. Marsilea drummondii has been recorded on a number of different soil types, ranging from sands to clays (Australian National Herbarium, Canberra, 2004).

Marsilea turns brown and forms sporocarps as the floodwaters receed. Coongie Lakes, NW Sth Aust.

From the air, receeding floodwaters expose large areas of browning Marsilea (foreground) at Coongie Lakes.

While the ground is still damp Marsilea forms a green carpet (foreground) with lignum behind. Coongie Lakes.

"Status" in community

Marsilea drummondii is frequently the dominant species in the herbaceous zone, especially on mudflats during and after flooding (Cunningham et al., 1981).

Associated species

No species are recorded as particular associates for M. drummondii given its wide ecological latitude and occurrence in a variety of vegetation communities. Associated species and vegetation communities recorded on specimen labels in the Australian National Herbarium include Eucalyptus camaldulensis open forest (with Acacia stenophylla and Muehlenbeckia florulenta), Eucalyptus largiflorens association, Juncus spp., Myriocephalum rhizocephalus, mixed herb-sedgeland, Triglochin sp. Typha domingensis and T. orientalis.

Qualitative and quantitative data – abundance, cover, biomass

No specific data is available relating to cover, abundance or biomass. However, as noted above, M. drummondii can be the dominant ground cover following flooding with receding waters, in some cases reaching 100% cover.

Species – interactions with other biodiversity

The sporocarps are eaten by waterfowl (Jones, 1998).

Physiological traits & adaptations

Marsilea drummondii is well adapted to arid and semi-arid environments and is able to respond to changing water levels. Spore production and germination can be triggered by variations in moisture. Plants survive well on damp mud, but with the desiccation of the soil, the leaves shrivel and the sporocarps become detached and dry, some lodging in the cracks of the drying mud where they can remain viable for 20-30 years. When substantial inundation again occurs, the sporocarps open and new plants are eventually produced (Aston, 1973).

Under certain seasonal conditions M. drummondii contains extremely high levels of thiaminase I activity. This can induce a thiamine deficiency in sheep feeding on the species (McCleary and Chick, 1977). The nardoo diet of members of the Burke and Wills expedition (1860-1861) exacerbated their decline in health due to high levels of the enzyme Thiaminase (Jones, 1998).

Reproduction and Establishment

Reproduction

Fruiting is rare in water but occurs on drying mud as the water recedes. Spores are contained in solitary or clustered hard sporocarps on unbranched stalks 10-50 mm long. Sporocarps only split after substantial immersion in water. Some sporocarps remain hard and closed for many years (up to 50) and do not open even after several floods (pers. comm., D.L. Jones, 2004). Sporocarps have been recorded from November to March (Aston, 1973; Jones, 1998; pers. comm., D.L. Jones, 2004).

Dispersability; establishment and growth

Sporocarps are probably dispersed by waterfowl since they pass undamaged through their digestive tract (Jones, 1998). Dispersal also occurs by floodwaters and probably by wind (pers. comm., D.L. Jones, 2004). When flooding occurs the sporocarps release their spores, leading to the establishment of new plants (Cunningham et al., 1981). Marsilea drummondii grows throughout the year, provided moisture conditions are favourable (Cunningham et al., 1981).

Juvenile period

Plants grow rapidly and can form sporocarps within three months (Cunningham et al., 1981).

Hydrology and salinity

Hydrology

The distribution of Marsilea drummondii is intimately linked with the flooding regimes of inland Australia.

Salinity tolerance

A salinity range of 0.2 – 0.3 ppt T.D.S. has been recorded for M. drummondii (Yezdani, 1970 in Aston, 1973).

Flooding regimes

In northern Victoria, M. drummondii has been found where flooding occurs in spring-summer, lasts one to six months, and is shallow (less than 10 cm deep) (Ward, 1996 in Roberts and Ludwig, 2000).

Change in water regimes

Short term floods result in little germination. Those plants that do germinate die without establishing or reproducing (pers. comm., D.L. Jones, 2004).

Response to disturbance (non-hydrological)

Grazing

Marsilea drummondii is usually eaten sparingly and survives grazing well (Cunningham et al., 1981).

Conservation status

This species is widespread in inland Australia and is not considered to be at risk.

Uses (including ethnobotanical)

Nardoo is a food plant for aboriginal people, who gather the sporocarps, grind them, and mix the powder with water (Aston, 1973) to form an edible dough (Cunningham et al., 1981). It is regarded by some as a useful forage plant but it is probably very low grade fodder. It is generally not favoured by stock when alternative feed is available. It is claimed to cause poisoning in sheep, horses and cattle. However, ingestion does not always result in poisoning (Cunningham et al., 1981).

Marsilea drummondii is a popular horticulture subject and is widely cultivated as a garden pond plant.

Summary

Marsilea drummondii is a common and widespread component of the herbaceous layer of wetland communities in inland Australia. Its lifecycle is closely tied to changes in water regimes, and reproduction and germination is almost completely dependent on cycles of flooding and drying. It has a low salinity tolerance and is potentially a species that may provide useful indication of health of mudflats as well as being a suitable plant for monitoring purposes. It plays an important part in the diet of aboriginal people in the semi-arid and arid parts of Australia.

References

Aston, H.I. (1973) Aquatic plants of Australia: a guide to the identification of the aquatic ferns and flowering plants of Australia, both native and naturalized, pp. 37-39. Melbourne University Press, Carlton.

Australian National Herbarium, Canberra. (2004). Australian National Herbarium Specimen Information Register. Available at: http://www.anbg.gov.au/cgi-bin/anhsir [Accessed: 2004, June].

Cunningham, G.M., Mulham, W.E., Milthorpe, P.E. and Leigh, J.H. (1981) Plants of Western New South Wales, p. 32. Soil Conservation Service of New South Wales.

Jones, D.L. (1998) Marsileaceae. In Flora of Australia, Volume 48, Ferns, Gymnosperms and Allied Groups, pp.166-173. ABRS/CSIRO Australia.

McCleary, B.V. and Chick, B.F. (1977) The purification and properties of Thiaminase I enzyme from Nardoo (Marsilea drummondii). Phytochemistry 16, 207-213.

Roberts, J. and Marston, F. (2000) Water Regime of Wetland and Floodplain Plants in the Murray-Darling Basin: A Source Book of Ecological Knowledge. CSIRO Land and Water, Technical Report 30-00

Wakefield, N.A. (1955) Ferns of Victoria and Tasmania: with descriptive notes and illustrations of the 116 native species, p. 56. Field Naturalists Club of Victoria, Melbourne.