"that ice-cream-tub-like riccia arrangement" is a pottery plant pot upside down with a stretchy "sock" of nylon netting pulled over it.
The nylon netting is actually a nylon shower loofah bought from k-mart. The loofah is just a long tube of nylon netting bunched up and tied with a string like a pom-pom. It even comes in green
When cut up it forms a perfect riccia net.