Identification: Fungus identification help required

I found this fungi growing in my house and need help understanding what it is and is it dangerous to humans in an enclosed space?

I appreciate the help

 

Your fungus is the cup-fungus Peziza varia (Ascomycetes, Pezizales). Synonyms are P. cerea, P. micropus, and P. repanda sensu auct. The species occurs both out-of-doors and inside buildings. It grows in a variety of substrates (including wood), being well-known of its tendency to prefer mortar, plaster, brickwalls and basements. It is harmless but may be difficult to erase from walls that contain some moisture or absorb moisture from the atmosphere.

Cheers, Harri Harmaja
http://www.fmnh.helsinki.fi/users/harmaja/index.htm

 

How on earth does it manage to grow on those? They are not exactly known for their organic carbon content - or does it have other ways of getting energy out of them? Cold nuclear fusion??

 

Thanks Harri.