crusts sunny coastal stone walls orange

Size
Width: 2–15 cm
Lifespan
10–30 years
Diet
Obtains nutrients via symbiotic partnership. Fungus provides structure. Alga provides photosynthetic food. Requires clean air and good light.
Habitat
Grows on rocks, stone walls, and occasionally bark in sunny, exposed locations. Forms bright orange to orange-yellow, crustose patches.
Range
Found throughout the North and South Islands on rocks, stone walls, and occasionally bark in sunny, exposed locations. Most common in coastal areas and on stone walls in urban and rural settings. Also found in temperate and coastal regions worldwide.
Endemism
Native
Main Threats
None significant. This species is common and widespread on rocks and stone walls. Localised threats include quarrying of rock outcrops, removal of stone walls, and air pollution.
Population
Not Threatened. This is a common and widespread lichen in New Zealand, particularly in coastal areas and on stone walls in urban and rural settings. It grows on rocks, stone walls, and occasionally on bark.
Conservation Status
Not Threatened
Human Risk
harmless
Handling Note
crustose lichen, safe to handle
Conservation Note
Native lichen; not assessed by NZTCS as lichens are generally outside the scope of current threat classifications.
Te Ao Māori
No recorded Māori name distinguishes the orange crust lichen from other lichens. Lichens were generally called pūkohu (mosses and lichens) or pukorokoro (crustose lichens). The bright orange patches would have been noticed. They looked like the colour of the sunset. Like the markings on a bird. But no distinct name survives. The orange crust lichen was sometimes used as a dye. The orange pigment could be extracted. It was used to colour fibres. Producing shades of yellow and orange.
It is not paint. It is alive. Orange crust lichen looks like a splash of paint. It has a body that is a thin, crusty layer. It grows on the surface of the rock. It forms a bright orange patch. The colour is a vivid orange-yellow. Sometimes almost fluorescent. It is the lichen of the stubborn stain. The one that is impossible to peel away. The one that makes the grey rock look like it has been tagged by a graffiti artist. What makes it special is the colour. The orange crust lichen is one of the brightest lichens in New Zealand. Its vivid orange-yellow colour stands out against the grey rock. It is visible from a distance. The colour comes from a pigment called parietin. It acts like a sunscreen. It protects the algae from intense sunlight. The more sun, the brighter it gets. In the shade, it fades to a pale yellow. It is the lichen of the sunny spot. The one that only shows its true colours in the full glare of the sun. The orange crust lichen is a crustose lichen. It grows flat on the rock. Like a crust of paint. Rather than upright or leafy. Its body is a continuous crust. Often cracked and irregular. It forms circular patches or spreading stains. It is firmly attached to the rock. Impossible to peel away without taking a piece of the stone with it. The surface is rough and granular. Like sandpaper. Biologically, the orange crust lichen is a partnership. A fungus and an alga live together. The fungus provides structure and protection. The alga provides food through photosynthesis. The orange crust lichen is a pioneer species. One of the first to colonise bare rock. It thrives in sunny, exposed locations where other lichens struggle. To find orange crust lichen is to find the bright stain on the rock. It is orange, crusty, and stubborn. A living splash of paint on the stone. You can run your finger over the surface. Feel the rough, crusty texture. It is the lichen of the stubborn stain. The one that is impossible to peel away. The one that proves that the most visible things are often the toughest.