About Calliergon giganteum (Schimp.) Kindb.
Calliergon giganteum, commonly known as giant spearmoss, giant calliergon moss, or arctic moss, is an aquatic moss that grows on lake beds in tundra regions. It does not produce woody stems or flowers, and has small rootlets in place of true roots. To survive the cold tundra climate, this species stores nutrients to use for producing new leaves in the spring. It can grow with less available nitrogen than any other known plant. It is one of roughly 2000 plant species native to the tundra, most of which are mosses and lichens. Migrating animals including birds eat this moss. In the Arctic, dense ground cover formed by Calliergon giganteum creates a warming effect that benefits other nearby plants. This species grows to approximately 8 centimeters in height. Its individual leaves live for at least four years, which may be the longest lifespan of leaves among any known moss. Calliergon giganteum prefers hydric environments, and grows best under consistently wet and humid conditions. For photosynthesis, its optimum water content ranges from 1500 to 1700 percent of the moss's total dry weight.
