Porella arboris-vitae Bitter Scalewort

A dioicous leafy liverwort which grows on dry, base-rich rocks and cliffs, or as an epiphyte on ash and hazel, particularly in shaded ravines. The very dark brownish-green colonies are made up of shoots with closely appressed leaves that curve downwards. It is a Submediterranen-Subatlantic species which is widespread but local in Britain with a largely western and northern distribution. It is rare in south Wales and was recorded by H.H. Knight from Cwnllynfell in 1906, but there are no recent records of it in West Glamorgan. Most plants in Britain are female and sporophytes are unknown here.