Tuesday, March 31, 2009

Living fossils

I found these strange, spore-producing shoots of field horsetail Equisetum arvense on a grassy bank near Durham city this afternoon. Known as the 'devil’s guts' to gardeners, on account of its devilish creeping underground rhizomes and resistance to herbicides that together make it almost impossible to eradicate, it produces this yellowish spore stalk first and green shoots only after these have shed their spores and withered away. Field horsetail grows to a height of around 30cm., but back in the Carboniferous, about 300 million years ago, plants that were 10 metres tall but otherwise identical flourished in steamy primaeval swarms. Like present-day horsetails, these gigantic ancestors’ stems were rich in silica and so were slow to decay, leaving excellent fossils whose basic features are almost identical to those of their present-day descendants. When I tapped the sporangia pictured here they release clouds of spores that drifted away on the wind......and if you want to see what these remarkable spores look like visit this post on my other blog, Beyond The Human Eye

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