The New Zealand bracken fern rhizome, <i>Pteridium esculentum (G.Forst)</i>: a toxic food plant of pre‐European Māori

ABSTRACT The two species of bracken fern, Pteridium esculentum and aquilinum , are well known to produce neoplastic lesions thiamine deficiency when consumed by mammals, with severe consequences health. New Zealand Pre‐European Māori have rhizomes P. as food little or no recorded Processing methods prior consumption may helped detoxify this food. We carried out LDH toxicity tests on that had been pre‐processed before simulated digestion test possibility. tested harvested each month the year, different components rhizome, both raw roasted rhizomes, stored for up 12 months, leached 24 hours. All specimens remained equally toxic within experimental error. a detailed analysis nutrients in rhizome compared kūmara, Ipomoea batatas another important plant pre‐European Māori, found has c. 70% caloric value kūmara. A cost/benefit plants suggested reward effort is greatest kūmara modest amount. Analysis historic ethnographic observations relating from AD 1769 1840s provides complex contradictory evidence role economic system. Although there clear greatly favoured chewing fondness result presence one more secondary metabolites (PSM), such ecdysone, which be addictive. Our favours being essentially famine food, filling period between planting harvest ‘hungry gap’ October April southern hemisphere. However, it would also provided an source travellers, fern‐lands widespread. archaeological information did not unequivocal direct consumption. extreme tooth wear unique pattern first molar dislocation, attributed use teeth strip starch shown present at all periods prehistory. This contrary finding some other researchers.