"La Puce" wrote in message
oups.com...

K wrote:
By coincidence, I was at a talk yesterday by one of the country's
leading mycologists. The fungus grows steadily outwards, fruiting around
the outside, hence the expanding ring. You can form an estimate of the
age of the fungus but the diameter of the ring of fruiting bodies.

Since the spores aren't propelled in any way by the fungus, they are
dependent on air currents for their dispersal. It's hard to envisage a
mechanism whereby they would be carried outwards only.
If putting a plastic sheet down killed the fungus, then it wasn't by the
mechanism described.

There's something to do with the nutrients that the mushrooms seek in
the soil hence them moving outwards and spores falling on depleted soil
wouldn't do well.

....

Fairy rings have nothing to do with spores

As was pointed our previously, the mushrooms are produced by the mycelium
which is between 12 and 15 inches underground. The mycelium is the main
fungal body. Its the mycelium which pushes outwards which produce
mushrooms, nit mushrooms which produce the mycelium. Spores merely enable
fungi to colonise new areas with no mycyleum alreadt present.

quote

Understanding fairy rings requires an understanding of how mushrooms
grow. Like apples on an apple tree, the "mushrooms" we see are only
the reproductive fruit bodies of the "true" organism, which is called
a mycelium. The mycelium grows underground; it is a mass of elongated,
hungry cells that feed on nutrients, pushing and growing through the
substrate as long as there is food available.

When the substrate is evenly composed--that is, when the food supply is
constant and uninterrupted--the mycelium grows ever-outward, leaving
behind the nutrient-poor substrate it has consumed and pushing into new
territory. If the mycelium decides to produce mushrooms, the result is
a fairy ring. Many species produce mushrooms more or less annually.

quote

http://www.mushroomexpert.com/fairy_rings.html


michael adams

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I think that's the mechanism for the fungis to move
outwards. The spores collecting are an option, an organic one, which
works. Off course there's the wind, hence the 1m sheet outwards.