the floating crystalwort of NZ's still freshwater pools
- Size
- Width: 2–5 cm
- Lifespan
- 1–3 years
- Diet
- Grows on damp soil, stream banks, and disturbed ground in open, sunny locations. Requires consistent moisture, well-drained soil, and good light. Forms flat, rosette-like thalli that look like green crystals on the soil.
- Habitat
- Grows in still or slow-moving water, on damp mud, and along pond and stream margins. Forms floating green mats or flat, lobed rosettes on mud.
- Range
- Found throughout the North and South Islands on damp soil, stream banks, and disturbed ground in open, sunny locations. Most common in lowland areas with consistent moisture. Also found in temperate regions worldwide.
- Endemism
- Native
- Main Threats
- None significant. This species is common and widespread in damp, disturbed habitats. Localised threats include habitat loss from land development and drainage of wetlands.
- Population
- Not Threatened. Riccia crystalwort is common in still or slow-moving water, on damp mud, and along pond and stream margins throughout New Zealand. It is a widespread species found in temperate regions around the world.
- Conservation Status
- Not Threatened
The one that lives two lives is a shape-shifter of the liverwort world. In water, it forms floating mats, tangled, branching, bright green threads that drift on the surface like a green cloud. On damp mud, it forms flat, lobed rosettes, small, green, star-shaped patches that cling to the soil like a green star. It changes its form to suit its environment, equally at home in water or on mud. It is the liverwort of the dual life, the one that is adaptable in a slightly unsettling way.
What makes it special is the adaptability. Riccia crystalwort is one of the few liverworts that can live both submerged and emergent. It is equally happy floating on the surface of a pond or pressed against damp mud. It changes its form, its texture, its appearance, depending on where it finds itself. It is the liverwort of the shape-shift, the one that adapts to survive, the one that proves that flexibility is a form of strength.
The thallus has two distinct forms. In its floating form, the thallus is narrow, branching, and ribbon-like, forming loose, tangled mats. The branches are thin and delicate, drifting with the current. In its terrestrial form, the thallus is broader, lobed, and rosette-forming, lying flat against the mud. The colour is bright green to yellowish-green, often with a translucent quality. Under a hand lens, the difference is striking, the same plant but completely different shapes.
Biologically, the riccia crystalwort reproduces by spores, released from capsules embedded in the thallus. It also reproduces by fragmentation, pieces broken off can grow into new plants. The spores are tiny, carried by the wind or water to new locations.
To find riccia crystalwort is to look at the surface of a still pond. There it is, a tangled green mat of bright green threads. Or look at the damp mud at the water's edge. There it is, a flat, lobed, star-shaped rosette. It is the liverwort of the two lives, the one that can live in water or on land, adaptable in a slightly unsettling way, the one that proves that home is wherever you make it.