collema jelly lichen swelling dark and rubbery after rain
- Size
- Width: 2–10 cm
- Lifespan
- 10–50 years
- Diet
- Grows on bark of trees, mossy rocks, and rotting logs in damp, shaded forests. Requires clean air, stable bark or rock surfaces, and high humidity. Tolerates shade and moisture but cannot survive prolonged drought.
- Habitat
- Grows on the bark of trees, on mossy rocks, and on rotting logs in damp, shaded forests throughout New Zealand. A creature of the wet bark, the damp rock, the places where the water trickles and the surface stays moist. Found from sea level to the montane zone, particularly in humid, sheltered locations where the forest is old and the air is damp. The lichen of the jelly, the one that remembers what it was like to be alive when it gets wet.
- Range
- Found throughout the North and South Islands on bark of trees, mossy rocks, and rotting logs in damp, shaded forests. 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 forests. Localised threats include forest clearance, air pollution, and climate change reducing forest floor humidity.
- Population
- Not Threatened. Collema jelly lichen is common in damp, shaded 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 a piece of seaweed on the tree has a body that is leafy, with broad, rounded lobes that are dark olive-green to blackish when dry. But when it gets wet, it transforms. The lobes swell and become soft, gelatinous, and translucent, like a piece of dark jelly or a wet leaf. It is the lichen of the transformation, the one that briefly remembers what it was like to be alive when the rain comes, the one that looks dead until the water touches it.
What makes it special is the jelly. The collema jelly lichen is one of the few lichens in New Zealand that is gelatinous when wet. Its lobes are thick and rubbery, filled with a gelatinous substance that absorbs water like a sponge. When it rains, the lichen swells to several times its dry thickness, becoming soft, pliable, and almost translucent. When it dries out, it shrinks and becomes dark, brittle, and curled. It is the lichen of the resurrection, the one that comes back to life with every rain, the one that proves that even the driest thing can be revived.
The collema jelly 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 surface is smooth and shiny when wet, dull and wrinkled when dry. Under a hand lens, the texture is fascinating, a landscape of tiny bumps and depressions.
Biologically, the collema jelly lichen is a cyanolichen, it contains cyanobacteria (blue-green algae) instead of the green algae found in most other lichens. The cyanobacteria give the lichen its dark colour and its gelatinous texture. They also give it the ability to fix nitrogen from the atmosphere. The collema jelly lichen is a natural fertiliser, adding nitrogen to the forest canopy.
To find collema jelly lichen is to find the dark, jelly-like patch on the bark. It is dark, rubbery, and alive, a living jelly on the tree. You can touch it when it is wet and feel the soft, gelatinous texture. It is the lichen of the transformation, the one that briefly remembers what it was like to be alive when the rain comes, the one that proves that the forest is full of surprises.