Walking through some desolate woods, a mossy rocks nestles into itself for warmth. Moss is a category of soft, photosynthesizing plants that have a non-vascular system. Unlike most plants which use a vascular system, moss does not have any vessels to transport water and sugar. Instead, the structure of the moss is such that it can trap water all throughout itself to prevent it from evaporating. Moss can survive in conditions with limited nutrients, and it would make for a wonderfully comfortable lawn.