Peperomia serpens

This species thrives as a house plant or in a terrarium.  It has heart-shaped leaves that grow to about 1 inch.  It grows throughout the amazon and often grows in dense mats on large fallen trees, especially overhanging small streams. It is more succulent than many of the Peperomaias grown in terrariums.   When planted on a wood surface, it will climb somewhat quickly and robustly up.  The pattern it makes is usually a zigzag pattern, and I have seen it climb about 2?, but it can likely go higher if given room.  It is an unexpected plant to cover a background, but does rather well at it, forming a loose aggregate of leaves that still allows the wood surface to be seen.

There are three localities pictured here, including one from Ecuador, one from the Sira Mountains, and one from Peru.