screws tight on the sunny stone walls

Size
Height: 1–3 cm
Lifespan
5–10 years
Diet
Photosynthetic. Grows on rocks, stone walls, and boulders. Requires stable rock surfaces, good light, and well-drained conditions.
Habitat
Grows on stone walls, rocks, and buildings in exposed, sunny locations. Forms small, dense, greyish-green cushions that cling tightly.
Range
Found throughout the North and South Islands on rocks, stone walls, and boulders. Most common in high country and volcanic plateau.
Endemism
Native
Main Threats
None significant. This species is common and widespread on rocks and stone walls. Localised threats include quarrying and removal of walls.
Population
Not Threatened. Wall screw moss is common on stone walls, rocks, and buildings throughout New Zealand, particularly in urban areas.
Conservation Status
Not Threatened
Human Risk
harmless
Handling Note
common moss, safe to handle
Conservation Note
Native moss; not assessed by NZTCS as bryophytes are generally outside the scope of current threat classifications.
Te Ao Māori
No recorded Māori name distinguishes the wall screw moss from other mosses. Mosses were generally called pūkohu (mosses and lichens) or rimu (a general term for small, low-growing plants). The moss on the stone walls would have arrived with European settlement, spreading through urban and disturbed habitats. The wall screw moss was not used in traditional Māori medicine or craft. It is a moss of the city, the stone wall, the building, a newcomer that has made itself at home in our urban landscapes.
There is no soil here. Tortula muralis looks like it is holding on for dear life. It has stems that are short and upright. Forming small, dense, greyish-green cushions on the surface of the stone. The leaves are narrow and pointed. With a distinctive, white, hair-like tip called an awn. It extends beyond the leaf tip. When dry, the leaves curl and twist. Giving the cushion a shaggy, unkempt appearance. When wet, they unfurl and turn bright green. It is the moss of the tight grip. The one that clings to stone like it is paying rent. What makes it special is the tenacity. Wall screw moss is one of the most tenacious mosses in New Zealand. It grows on vertical stone walls. On rooftops. On the sides of buildings. Places where there is no soil. No organic matter. Nothing but bare stone. It holds on with its rhizoids. Root-like structures that penetrate the microscopic pores of the stone. Anchoring it firmly. You can try to scrape it off. You will fail. It is the moss of the stone. The one that pays its rent in persistence. The one that never lets go. The leaves are narrow and pointed. With a long, white, hair-like tip. It reflects sunlight and traps moisture. The leaf surface is covered in tiny, papillose bumps. Giving it a rough, textured appearance. When dry, the leaves twist and curl. Reducing water loss. Under a hand lens, the white awns are visible. Tiny glassy threads extending from each leaf tip. Biologically, the wall screw moss reproduces by spores. Released from capsules on tall stalks. The capsules are cylindrical and curved. With a long, twisted peristome. The screw that gives the moss its name. The spores are tiny. Carried by the wind to new walls. To find wall screw moss is to find the greyish-green cushions on the old stone wall. They are small, dense, and clingy. A living payment on the stone. You can try to scrape it off. See how it holds on. It is the moss of the tight grip. The one that clings to stone like it is paying rent. The one that proves that persistence pays off. No recorded Māori name distinguishes the wall screw moss from other mosses. Mosses were generally called pūkohu or rimu. The moss on the stone walls would have arrived with European settlement. Spreading through urban and disturbed habitats. The wall screw moss was not used in traditional Māori medicine or craft. It is a moss of the city. The stone wall. The building. A newcomer that has made itself at home in our urban landscapes.