Nardoo, an Australian Icon

Marsilea species
Family: MARSILEACEAE
Marsileas occur around the world, but have a special place in both Aboriginal and white Australian culture. They were a very important food source for aborigines, before white settlement
They also have a place in our history books as the plant on which the explorers Burke and Wills allegedly starved to death. When they ran out of food, the hungry explorers were shown by aborigines that they could eat nardoo sporocarps. They may have also been shown how to prepare them, but the history books are silent on this point. Correct preparation involves soaking to leach out a substance called thiaminase, which destroys vitamin B1.
Wills’s last journal entry comments “starvation on nardoo is by no means very unpleasant, but for the weakness one feels, and the utter inability to move oneself, for as far as appetite is concerned, it gives me the greatest satisfaction”. These symptoms describe beri-beri, a disease caused by vitamin deficiency. Poor Wills was probably not starving at all.
Nardoo is actually a kind of fern, as you can see from examining new leaves. They unroll in classical fern-frond style. It’s unusual in having its spores in capsules arising from the stems, rather than the usual fern arrangement of fuzzy brown patches on the backs of the fronds.
I notice that pressed specimens of the silvery-leafed common nardoo, Marsilea drummondii, can be bought in newsagents labelled “lucky four-leaf clover”. They are a pretty ornament, but I question what sort of luck might be received by someone who tries to cheat in this way!
As water plants go, nardoos are remarkably drought resistant, especially in heavy clay soils. The hardiest of our three local species is Marsilea hirsuta. It has plain green leaves and is a plant of periodically flooded soils - only marginally a “water plant” at all. Next hardiest is the common nardoo M. drummondii, whose range extends from floodplains to water 30cm deep. In water, the leaves are plain green, but on dry land they are covered with fine silvery hairs - very pretty. Both these plants cope with drought by dying back to their underground roots, and waiting for the rains to give them a new lease on life. The sporocarps can survive in dry soil for at least 100 years!
The best nardoo for deeper ponds and dams is the one with patterned leaves, M. mutica (pictured above), which grows in water to 1m deep, (as well as wet soil).
Nardoos thrive in both acid and alkaline conditions, survive frosts, grow in full or part sun, can be kept in pots, and are generally a trouble-free plant for gardens.