Selaginella is a large genus of plants commonly known as clubmosses or spike mosses that are widely distributed around the globe. Approximately 600 species of Selaginella have been identified, and these exhibit significant variation in their structure, appearance, and preferred habitat. Some of the vascular plants appear similar to ferns and proliferate predominantly in the tropics, whereas others display simple scale-like leaves and creep across the ground like mosses. Several species of Selaginella are especially adapted for arid conditions. Often referred to as resurrection plants, these species curl up into what appears to be a lifeless ball of material when dry, but unfold into a much more vibrant, leafy form when exposed to water. Dried resurrection plants are often marketed as novelty items.