07 March 2013

Bracken Fern

When Tom and Elizabeth took the farm
The bracken made their bed,
And Quardle oodle ardle wardle doodle
The magpies said.

So starts one of New Zealand's better known poems by Denis Glover - and the poem ends

The farm's still there. Mortgage corporations
Couldn't give it away.
And Quardle oodle ardle wardle doodle
The magpies said.

And in between those two verses lies the struggle and failure of Tom and Elizabeth in the battle for their farm. Eventually bracken which, initially, they used for bedding took over the land.

Bracken is one of the most ubiquitous plants on earth, locally intensive and globally extensive it is limited only by the extremes of latitude and altitude - and available moisture. It is one of the most ancient of plants. Given relief from herbivory it will colonize open areas and is part of a natural progression towards reforestation.

Bracken Covered Hillside

Perhaps relatively harmless in the natural world it has been a major source of trouble in the herbivorous world of the marginal grazing farm. It causes a number of syndromes which include both acute haemorrhagic toxicity and cancer in herbivores.  It has also been suggested as causing cancer in man in several countries, either through the direct consumption of bracken croziers or indirectly via meat or milk.

That is just a little about bracken fern.  There is much more. It has had a close association with man, both as food, comfort and shelter and for his domestic animals. I wonder what role, if any, ancient bracken (400mya), with its DNA hungry carcinogen, might have played in evolutionary change?

NZ Bracken Frond

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