lecidea crust lichen of bare rock in high alpine zones
- Size
- Width: 2–10 cm
- Lifespan
- 10–50 years
- Diet
- Grows on rocks, boulders, and stone walls in open, sunny locations. Requires clean air, stable rock surfaces, and good light. Tolerates sun, wind, drought, and extreme temperatures.
- Habitat
- Grows on rocks, boulders, and stone walls in open, sunny locations. Found from sea level to alpine zone on native and introduced rock types.
- Range
- Found throughout the North and South Islands on rocks, boulders, and stone walls in open, sunny locations. Most common in the South Island's high country and the North Island's volcanic plateau. Also found in temperate and cold 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. Lecidea crust lichen is common and widespread in New Zealand, particularly on rocks and stone walls in sunny, exposed locations. It grows on native and introduced rock types.
- Conservation Status
- Not Threatened
The one that looks like a dark stain on the rock has a body that is a thin, crusty layer that grows on the surface of the stone, forming a dark grey to blackish-brown patch. The colour is a deep, sooty grey, sometimes with a hint of brown or green. It is the lichen of the dark crust, the one that fades into the rock like a shadow, the one that is easy to miss but hard to ignore once you see it.
What makes it special is the understatement. Lecidea crust lichen is one of the least conspicuous lichens in New Zealand. Its dark colour blends perfectly with the dark, weathered rock, especially in shaded or overcast conditions. You can walk right past it without noticing. It does not demand attention. It does not want to be seen. It is the lichen of the hidden presence, the one that is there but not there, the one that proves that the most successful strategy is sometimes just to disappear.
The lecidea crust lichen is a crustose lichen, meaning it grows flat on the rock, like a crust of paint, rather than upright or leafy. Its body is a smooth or cracked crust, often forming irregular patches that spread across the rock. The surface is often dotted with tiny, black discs (apothecia) that are the spore-producing structures. Under a hand lens, the discs are visible, tiny black buttons on the dark surface.
Biologically, the lecidea crust lichen is a partnership, a fungus and an alga living together. The fungus provides structure and protection. The alga provides food through photosynthesis. The lecidea crust lichen is a pioneer species, one of the first to colonise bare rock. It grows very slowly, a few millimetres per year, and a large patch may be decades old.
To find lecidea crust lichen is to find the dark stain on the rock. It is dark, crusty, and hidden, a living shadow on the stone. You can run your finger over the surface and feel the smooth, crusty texture. It is the lichen of the dark crust, the one that fades into the rock like a shadow, the one that proves that the most effective camouflage is to look like nothing at all.