chainmails the damp shaded tree trunks

Size
Width: 2–5 cm
Lifespan
3–7 years
Diet
Obtains nutrients via photosynthesis. Requires consistent moisture and high humidity. Grows on bark, rocks, and wood in shaded forests.
Habitat
Grows on bark of trees, rocks, and wood in damp, shaded forests. Forms scaly, leafy mats that look like chainmail on the trunk.
Range
Found throughout the North and South Islands on bark of trees, rocks, and wood in damp, shaded forests. Most common in lowland and montane forests with high rainfall. Endemic to New Zealand, found nowhere else in the world.
Endemism
Endemic
Main Threats
None significant. This species is common and widespread. Localised threats include forest clearance, removal of old trees, and climate change reducing forest floor humidity.
Population
Not Threatened. Scaly liverwort is common on the bark of native trees throughout New Zealand, particularly in damp, shaded forests. It is endemic to New Zealand, found nowhere else in the world.
Conservation Status
Not Threatened
Human Risk
harmless
Handling Note
common liverwort, safe to handle
Conservation Note
Endemic liverwort; not assessed by NZTCS as bryophytes are generally outside the scope of current threat classifications.
Te Ao Māori
No recorded Māori name distinguishes the scaly liverwort from other liverworts. Liverworts were generally called pūkohu (mosses and lichens). The scaly, armoured mats on the bark would have been noticed. They looked like the scales of a fish. Like the armour of a warrior. But no distinct name survives. The scaly liverwort was known for its effects. It was used in traditional medicine. And possibly in spiritual practices. The compound perrottetinene produces mild psychoactive effects. And the liverwort may have been used as a relaxant or an aid to meditation.
Without it, the bark is just wood. With it, there is chainmail. Radula marginata looks like it is wearing armour. It has stems that are creeping and branching. Forming dense, leafy mats on the bark. The leaves are tiny. Less than a millimetre long. Arranged in two rows along the stem. Overlapping like the scales of a fish or the plates of armour. Each leaf is rounded and concave. With a distinct margin that gives it a scalloped edge. The colour is pale green to yellowish-green. Often with a translucent quality. It is the liverwort of the armour plate. The one that looks like it is protecting something soft underneath. The one that is both beautiful and defensive. What makes it special is the chemistry. Scaly liverwort is one of the most chemically interesting liverworts in New Zealand. It produces a compound called perrottetinene. Which is structurally similar to THC. The active compound in cannabis. This compound has psychoactive properties. And has been used in traditional medicine and recreation. It is the liverwort of the chemistry set. The one with a secret ingredient. The one that has been known to Māori for centuries. The leaves are arranged in two rows along the stem. With the lobes overlapping like roof tiles. The leaf margin is entire (smooth). And often has a distinct border of darker cells. The underleaf (amphigastrium) is present but small. Often hidden by the overlapping leaves. Under a hand lens, the overlapping scales are visible. A perfect mosaic of green and pale green. Biologically, the scaly liverwort reproduces by spores. Released from capsules on short stalks. It grows on the bark of native trees in damp, shaded forests. It is endemic to New Zealand. Found nowhere else in the world. A unique part of our natural heritage. To find scaly liverwort is to find the tiny, scaly mats on the tree bark. They are pale green. Overlapping. And armoured. A living chainmail on the trunk. You need a hand lens to see the overlapping scales. The scalloped edges. The armour for something softer. It is the liverwort of the chemistry set. The one with a secret ingredient. The one that proves that the smallest things can have the biggest secrets.