The one that looks like a tangled ball of string has a body that is pale greenish-yellow to olive-brown, with long, stringy strands that hang from the branches like a tangled net. The strands are thin and wiry, often reaching 10 to 20 centimetres in length. They are branching and intertwining, forming a dense, matted curtain on the branches. It is the lichen of the tangled string, the one that sways with the weather. What makes it special is the texture. The string lichen is one of the most stringy lichens in New Zealand. Its strands are thin and wiry, like pieces of string or thread. They are branching and intertwining, forming a dense, tangled mass. The colour is a pale greenish-yellow to olive-brown, often darker than other fruticose lichens. It is the lichen of the hanging garden, the one that turns the tree into a living curtain, the one that moves with the wind. The strands are elastic and tough, not brittle like other fruticose lichens. They can be stretched and twisted without breaking. The surface is smooth and shiny, often covered in tiny, white spots (pseudocyphellae) that help the lichen breathe. Under a hand lens, the white spots are visible, tiny pores scattered across the surface of the strands. Biologically, the string lichen is a partnership, a fungus and an alga living together. The fungus provides structure and protection. The alga provides food through photosynthesis. The string lichen is also a bioindicator. It is sensitive to air pollution, particularly sulphur dioxide. In polluted air, it dies. It is the canary of the canopy, the one that tells us whether the air is healthy. To find string lichen is to find the tangled string on the branch. It is pale, stringy, and tangled, a living curtain on the tree. You can run your fingers through the strands and feel the wiry, stringy texture. It is the lichen of the tangled string, the one that sways with the weather, the one that proves that the cleanest air holds the strangest beauty.