http://100percentcork.orgLike I said, I don't know, it could be synthetic cork. It looks like natural cork in some places but it doesn't mean it is.
Google has an answer for everything. Not necessarily a correct answer, but an answer.
Reading just a tiny bit, there does appear to be a fungus that grows on some natural cork. The fungus actually is green, but it's not slimy -- unless you submerge it in liquid for awhile (generally wine, natch).
Maybe it's something that's growing on the adhesive. Maybe it's something brand new. Hey, you could have a fungus named after you!