the brown foliose lichen of NZ's forest understorey
- Size
- Width: 5–15 cm
- Lifespan
- 10–50 years
- Diet
- Grows on bark of trees, mossy rocks, and rotting logs in damp, undisturbed forests. Requires clean air, stable bark surfaces, and high humidity. Tolerates shade and moisture but cannot survive prolonged drought.
- Habitat
- Grows on bark of trees, mossy rocks, and rotting logs in damp, undisturbed forests. Forms leafy, curled lobes that look like they are mid-thought.
- Range
- Found in the South Island's beech forests and the North Island's western ranges. Most common in damp, undisturbed forests with high rainfall and clean air. Also found in Australia and South America.
- Endemism
- Native
- Main Threats
- None significant. This species is common and widespread in damp, undisturbed forests. Localised threats include forest clearance, air pollution, and climate change reducing forest floor humidity.
- Population
- Not Threatened. Nephroma lichen is common in damp, undisturbed forests throughout New Zealand, particularly in the South Island's beech forests and the North Island's western ranges. It grows on the bark of native trees, on mossy rocks, and on rotting logs.
- Conservation Status
- Not Threatened
The one that looks like it is thinking has a body that is leafy, with smooth, rounded lobes that curl up at the edges like the pages of a book or the lip of a shell. The upper surface is pale greyish-green to brownish-green when dry, bright green when wet. The lobes are broad and smooth, often with a slightly glossy sheen. It is the lichen of the curled edge, the one that looks like it is mid-thought, the one that seems to be reaching for something just out of reach.
What makes it special is the curl. The nephroma lichen is one of the few lichens in New Zealand with consistently curled lobe margins. The edges of the lobes curl upward, revealing the pale, white or pale brown underside. The curl gives the lichen a three-dimensional quality, as if it is lifting itself off the bark, reaching for something. It is the lichen of the curled lip, the one that looks like it has something to say, the one that seems to be listening to the forest.
The nephroma lichen is a foliose lichen, meaning it grows in flat, leafy lobes that are attached to the substrate at points but not completely stuck down. The lobes are broad and rounded, often with a wavy or lobed margin. The upper surface is smooth and shiny, often with a network of fine, white lines. The underside is pale, with a sparse mat of rhizines, tiny, root-like structures that anchor it to the bark.
Biologically, the nephroma lichen is a partnership, a fungus, a green alga, and a cyanobacterium living together. The fungus provides structure and protection. The green alga provides food through photosynthesis. The cyanobacterium provides nitrogen through fixation. It is a three-way partnership, a tiny ecosystem on the bark of an old tree.
To find nephroma lichen is to find the curled lobes on the bark. It is pale, smooth, and curled, a living thought on the tree. You can run your finger over the curled edge and feel the smooth, glossy surface. It is the lichen of the curling lobe, the one that looks like it is mid-thought, the one that proves that even lichens can have a contemplative side.