Spotted this mushroom growing out of the moss on one of my mini orchids in my terrarium. I took a series of shots, put them on the computer, picked out a good closeup but needed to reshoot one from farther away (to much glare from the florescent lights). The computer work took about 1/2 hour. In that time I bet the mushroom grew about 2mm (in height)
The inset is from the first set of pictures (to hot) but shows the size difference in that 1/2 hour time period. You can use the two little terraces of moss to the left of the mushroom to see the difference in height. The cap of the mushroom is around 4mm in diameter. Second picture is a different angle and closer
Take Nothing but Pictures--Leave Nothing but Footprints.
Doug Breda
Besides, I think orchids needed symbiotic relationship with some very very tiny mushrooms for propagation. 
)
Nice photos of the little ecosystem there Doug.