compact rustwort

<em>Marsupella condensata</em>, the compact rustwort, is a small leafy liverwort in the family Gymnomitriaceae found in Arctic and alpine habitats in Europe, with documented occurrences in Norway and Sweden. Liverworts in the genus Marsupella are characterised by their simple thalloid or leafy structure and specialisation for cold, wet, and exposed environments including snowflush communities, fellfields, and soliflucted soils at high elevation or high latitude. Compact rustwort typically grows in moist, acidic substrates near late-lying snow patches and on wet rock surfaces in montane tundra and alpine heath. These habitats are highly sensitive to climate change, with warming temperatures and reduced snowpack directly threatening snowflush plant communities across Scandinavia. The IUCN classifies <em>Marsupella condensata</em> as Least Concern, although its dependence on cold, moist microhabitats makes it potentially sensitive to long-term climate warming. The species contributes to biological soil crusts and serves as a substrate for invertebrates and microorganisms in fragile alpine ecosystems. Bryophytes like compact rustwort are often slow-growing and slow to recolonise following disturbance. Biological traits including growth rates, reproductive biology, and precise morphological measurements remain poorly documented, as is typical for many liverwort species outside specialist botanical surveys. Its conservation depends on the preservation of intact alpine and Arctic habitats across Scandinavia.