michael adams writes

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


A friend put down a plastic sheet all around the ring she had in her
lawn (her parents lawn actually - she would never get rid of hers),
forming a circle from the ring to about 1m wide outwards. The spores of
the fungi 'fly' outwards (hence the rings usually getting bigger year
after year) and were collected in the sheet.


The mushrooms in fairy rings are simply the visble evidence of fungal
strands
or mycelium which spread in the soil to a depth of 10 to 12 inches.
They don't propogate on the surface at all, so a plastic sheet could be
of no possible use.

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.

--
Kay