BRACKEN FERN (PTERIDIUM AQUILINUM)
Bracken fern (Pteridium aquilinum) is very common worldwide; here in Nova Scotia it colonizes cutover land, forest clearings, or burned areas. The young leaf blades are coiled, resembling the end of a violin, hence the name “fiddlehead,” which is loosely applied to the undeveloped leaves of all ferns. Fiddleheads start off covered in brown scales, then emerge rolled tightly and bent like a shepherd’s crook.
The mature fronds generally number three per plant and are carried on brownish stalks.
Unlike the edible fiddlehead fern, which grows on lowland and streamsides, bracken is generally found in upland, dry, or rocky sites.
It is toxic to both livestock and humans and has been incriminated in the high incidence of stomach cancer in Japan, where it is eaten as a vegetable.
Leaves and stems contain the latex.
The sap (sticky latex) contains several glycosides, the quantity and efficacy depending upon the species.
TYPICAL POISONING SCENARIO
Consumption of leaves and stems, by children or those seeking a herbal cure.
The glycosides are generally cathartic (purgative, laxative).
BRACKEN FERN POISON INFORMATION
Carcinogens and co-carcinogens
A plant is identified as carcinogenic when it is shown to cause cancer in persons touching or eating it.
A plant is said to be co-carcinogenic when it causes cancer only in conjunction with some other substance. Roquefort and camembert cheese moulds, daphne, and poinsettias, for example, can cause cancer only if the victim eats them while taking certain prescription drugs.
Glycosides are toxins in which at least one sugar molecule is linked with oxygen to another compound, often nitrogen-based. They become harmful when the sugar molecule is stripped off, as in the process of digestion.