Marcgravia sp. Brown Ecuador

This colorful Marcgravia from Ecuador has only produced immature leaves in the terrarium for me, and it stays very small (leaves under .5 inches, closer to .25 inches). It maintains the nice dark brown/red color and is one of the easiest Marcgravias to grow in my experience.  There is a possibility its mature leaves are larger, but it seems unwilling to produce these leaves easily in terrarium conditions.