mats the bark with geometric precision

Size
Width: 2–5 cm
Lifespan
3–7 years
Diet
Photosynthetic. Draws energy from sunlight. Requires consistent moisture, high humidity, and stable bark surfaces in old-growth forest.
Habitat
Grows on bark of trees, rocks, and wood in damp, shaded forests throughout New Zealand. A creature of the bark and trunk. Forms tiny, overlapping, leafy mats with geometric precision.
Range
Found throughout North and South Islands on bark of native trees, rocks, and wood. Most common in lowland and montane forests with high rainfall. Also found in temperate regions worldwide.
Endemism
Endemic
Main Threats
None significant. Common and widespread in damp, shaded forests. Localised threats include forest clearance, removal of old trees, and climate change reducing humidity.
Population
Not Threatened. Common on bark of native trees, rocks, and wood in damp, shaded forests throughout New Zealand. Widespread in temperate regions.
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 frullania liverwort from other liverworts. Liverworts were generally called pūkohu or grouped with other small, damp-loving plants. The dense, patterned mats on the bark would have been noticed. Looked like the scales of a fish. Like the pattern of a carving. No distinct name survives. Not used as medicine or dye. Too small. Too patterned. Too much a creature of the bark. Simply part of the forest.
It is not random. Frullania rostrata covers the bark in tiny tiles. Its stems 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 roof tiles. Each leaf is divided into two lobes. A large, rounded, dorsal lobe lies flat against the bark. A smaller, inflated, ventral lobe sticks out like a tiny balloon. The colour is dark green to reddish-brown. Often with a metallic sheen. The leaves are so densely packed that the stem is completely hidden. Creating a smooth, tiled surface. Looks almost manufactured. It is the liverwort of the obsessive pattern. The one that covers the bark in tiny, repeating tiles. What makes it special is the pattern. Frullania liverwort has one of the most intricate, obsessive patterns of any liverwort in New Zealand. The leaves are arranged in perfect, overlapping rows. Each leaf a tiny tile in a living mosaic. The pattern is so regular. So precise. It looks like it was designed by a machine. Under a hand lens, the pattern is mesmerising. Each leaf perfectly positioned. Each water sac precisely inflated. It is the liverwort of the obsessive detail. The one that covers the bark in a living quilt. The one that makes the tree trunk look like it has been paved with tiny green and brown tiles. The water sacs or ventral lobes are the key to survival. They store water. Allowing the liverwort to survive dry periods. When the air is damp, the sacs are plump and round. When it is dry, they shrink. Conserving moisture. The sacs also give the mat its bumpy texture. A landscape of tiny hills and valleys. Biologically, it reproduces by spores released from capsules on short stalks. It also reproduces asexually via gemmae. Tiny buds that break off and grow into new plants. To find frullania liverwort is to look at the bark of an old tree. There it is. A dense, leafy mat of tiny, overlapping leaves. Dark green to reddish-brown. Covering the bark in obsessive, repeating patterns. You need a hand lens to see the individual leaves. The water sacs. The perfect geometry. It is the liverwort of the obsessive pattern. The one that covers the bark in tiny, repeating tiles. The one that proves nature loves geometry as much as any mathematician. It carries on.