Glistening ink cap?

These were in my surburban garden in London. A huge patch of maybe 100 appeared overnight around the base of an old apple tree.

They were gone within 5 days, collapsed into a mass of black goo - hence I thought they might be a type of ink cap.

They were only 2 or 3 inches high at best and very soft and delicate.

Brand:	Canon
Camera:	Canon EOS 7D
Lens:	EF-S15-85mm f/3.5-5.6 IS USM
Recording media:	JPEG (digital)
Date Taken:	19 Nov 2011 - 10:59 AM
Focal Length:	85mm
Lens Max Aperture:	f/5.7
Aperture:	f/11.0
Shutter Speed:	1/13sec
Exposure Comp:	-1/3
ISO:	100
Exposure Mode:	Aperture-priority AE
Metering Mode:	Multi-segment
Flash:	Off, Did not fire

Title:	Glistening ink cap?
Username:	KatieR
Uploaded:	3 Dec 2011 - 2:02 PM