This plant goes by many names. Our current best description is Micranthemum glomeratum, but Hemianthus glomeratum, Hemianthus micranthemoides, and Micranthemum micranthemoides are all commonly used. Under high light conditions with CO2 injection, pearlweed generally creeps low over the substrate and can be trimmed to form a dense carpet. Under lower light without CO2, it will still creep, but tends to grow taller and a little more disorganized. It can also form dense floating mats and be used as cover for top dwelling fish, shrimp, or fry.