A heavily shaded softwood forest composed of mostly needle-bearing trees grows from acidic soil in this habitat. The forest floor is blanketed with moss, fallen trees, seasonal mushrooms, and conifer needles. The lush, green mosses dominate the scene since few leafy plants can thrive in such a damp, shady, and acidic environment. Although moss looks static from a distance, close observation reveals a delicate stalk-like spore-producing structure appearing from the end of leafy stems during sexual reproduction. Numerous species of lichens are also found in Coniferous Woods on the bark and branches of trees. Varieties such as old man’s beard passively absorb trace metals (e.g., mercury) and other pollutants from the air, making them excellent indicators of air pollution and acid rain.