leptogium jelly lichen dark and gelatinous after heavy rain
- Size
- Width: 2–8 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 bark of trees, mossy rocks, and rotting logs in damp, shaded forests. Forms blue-grey to brownish, gelatinous lobes that look fleshy after rain.
- 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. Leptogium 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 dead fish has a body that is leafy, with broad, rounded lobes that are blue-grey to pale greyish-brown when dry. But when it gets wet, it transforms. The lobes swell and become soft, gelatinous, and translucent, like a piece of raw fish or a slice of jelly. The colour becomes a deeper blue-grey, almost bruise-like. It is the lichen of the fleshy texture, the one that looks like it belongs in a seafood market, the one that makes you do a double take.
What makes it special is the colour. The leptogium jelly lichen is one of the few lichens in New Zealand with a distinctive blue-grey colour. The colour is caused by the cyanobacteria (blue-green algae) that live inside the lichen. When the lichen is wet, the colour deepens, becoming a rich, dark blue-grey. When it is dry, it fades to a pale, papery brownish-grey. It is the lichen of the changing colour, the one that shifts with the weather, the one that looks different every time you see it.
The leptogium 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. The underside is pale, with a sparse mat of rhizines, tiny, root-like structures that anchor it to the bark.
Biologically, the leptogium 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 blue-grey colour and its gelatinous texture. They also give it the ability to fix nitrogen from the atmosphere.
To find leptogium jelly lichen is to find the blue-grey jelly on the bark. It is soft, fleshy, 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 fleshy texture, the one that looks like it belongs in a seafood market, the one that proves that the forest is full of surprises.