lepraria dust lichen spreading powdery grey-green across bark
- Size
- Width: 2–10 cm
- Lifespan
- 10–30 years
- Diet
- Grows on rocks, bark, and soil in damp, shaded locations. Requires clean air, stable surfaces, and high humidity. Tolerates shade and moisture but cannot survive prolonged drought.
- Habitat
- Grows on rocks, bark, and soil in damp, shaded locations. Found from sea level to alpine zone in sheltered locations where the surface is stable.
- Range
- Found throughout the North and South Islands on rocks, bark, and soil in damp, shaded locations. Most common in the South Island's beech forests and the North Island's western ranges. Also found in temperate regions worldwide.
- Endemism
- Native
- Main Threats
- None significant. This species is common and widespread in damp, shaded locations. Localised threats include forest clearance, air pollution, and climate change reducing humidity.
- Population
- Not Threatened. Lepraria dust lichen is common and widespread in New Zealand, particularly in damp, shaded locations on rocks, bark, and soil. It is one of the easiest lichens to overlook because it looks like nothing in particular.
- Conservation Status
- Not Threatened
The one that looks like someone forgot to finish it has no structure, no lobes, no discs, no stalks. It is just a powdery, granular crust that spreads across the rock or bark like a patch of pale greenish-grey dust. It looks like a stain, like a discolouration, like the idea of a lichen rather than an actual lichen. It is the lichen of the unfinished thought, the one that looks like it gave up halfway through.
What makes it special is the formlessness. Lepraria dust lichen is one of the least structured lichens in New Zealand. It has no defined shape, no organised tissues, no visible fruiting bodies. It is a loose aggregation of powdery granules (soredia), each granule containing a few algal cells wrapped in fungal hyphae. It reproduces by these granules breaking off and blowing away to start new colonies. It is the lichen of the formless spread, the one that does not bother with structure, the one that is successful by being simple.
The lepraria dust lichen is a crustose lichen, or rather, it is what happens when a crustose lichen gives up on being a crust. Its body is a powdery, leprose (crumbly) layer that grows on the surface. The colour is pale greenish-grey to bluish-grey, often with a powdery, dusty appearance. Under a hand lens, the granules are visible, a loose collection of tiny greenish balls.
Biologically, the lepraria dust lichen is a partnership, a fungus and an alga living together. The fungus provides what little structure there is. The alga provides food through photosynthesis. The powdery granules are the reproductive structures, breaking off and dispersing to form new colonies.
To find lepraria dust lichen is to find the dusty patch on the rock. It is pale, powdery, and formless, a living stain on the stone. You will not be impressed. You will not take a photo. You will probably brush it off and forget it. But it is there, quietly spreading, being the idea of a lichen rather than the thing itself, the one that proves that you do not need to be complicated to survive.