Echinodorus cordifolius marble queen -Green is a variegated form of Echinodorus cordifolius. This variegation is more distinct in emersed than in submerged leaves. This Echinodorus is an easy, fast growing aquarium plant. It tolerates hard and alkaline water, but a nutrient-rich substrate and at least medium light intensity are beneficial. It has the tendency to grow out of the water with long-stalked aerial leaves.