The one that looks like a tiny orange bush has a body that is pale orange to bright orange-yellow, with branching, shrubby stalks that rise from the bark like a miniature coral. The stalks are thin and wiry, often reaching 1 to 3 centimetres in height. The tips are often curled or twisted, giving the lichen a frizzy, chaotic appearance. It is the lichen of the bright colour, the one that loves the sun and is becoming harder to find, the one that is a flash of warmth in the cool green forest. What makes it special is the colour. Teloschistes lichen is one of the brightest lichens in New Zealand. Its vivid orange-yellow colour stands out against the grey bark, visible from a distance. The colour comes from a pigment called parietin, which acts like a sunscreen, protecting the algae from intense sunlight. The more sun, the brighter it gets. In the shade, it fades to a pale yellow or greyish-yellow. It is the lichen of the sun lover, the one that needs the light, the one that is a barometer of clean air. The teloschistes lichen is a fruticose lichen, meaning it grows upright, like a tiny shrub, rather than flat on the bark. Its stalks are branching and bushy, often forming dense, rounded clumps. The surface is 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 orange surface. Biologically, the teloschistes lichen is a partnership, a fungus and an alga living together. The fungus provides structure and protection. The alga provides food through photosynthesis. The teloschistes lichen is sensitive to air pollution, particularly nitrogen compounds. It is the canary of the branch, the one that tells us whether the air is healthy, the one that disappears when we poison the sky. Why is it declining? Air pollution and habitat loss. Teloschistes lichen is sensitive to nitrogen compounds from car exhaust, fertiliser runoff, and stock urine. In areas with high nitrogen levels, it is replaced by other, more pollution-tolerant lichens. It is also sensitive to the loss of old trees with rough bark. To find teloschistes lichen is to find the bright orange bush on the branch. It is orange, branching, and sun-loving, a tiny coral on the tree. You can run your finger through the stalks and feel the wiry, brittle texture. It is the lichen of the bright colour, the one that loves the sun and is becoming harder to find, the one that proves that the most beautiful things are often the most fragile.