Riccia cavernosa Cavernous Crystalwort

A monoicous thallose liverwort which grows on exposed mud or damp sandy soils in seasonally flooded habitats such as dune slacks, the edges of pools, lakes and reservoirs and in wet quarries. It is a very distinctive crytalwort which forms small, yellow-green, circular, spongy rosettes with many lobes. It has a rather sparse but widespread distribution in southern Britain but it is fairly scarce and mostly coastal in Wales. It is uncommon in West Glamorgan but often forms abundant colonies on bare damp sandy, dune slack soils in the vicinity of Morfa Dunes, although populations can be rather ephemeral. It is a good coloniser and produces relatively large spores which appear to remain viable in  the soil for a long time. It fruits abundantly in summer and autumn.