Reboulia hemisphaerica Hemisphaeric Liverwort

An autoicous thallose liverwort which grows on calcareous soils or on rocks and boulders, particularly on limestone. Like Targionia hypophylla, it is disiccation tolerant and does best in sites where there is at least a short period of seasonal drought. It is similar to Pressia quadrata but its thallus is a paler or glaucous green, has inconspicuous air pores and does not have a bitter taste. It has a patchy distribution in Britain, mostly in the west and north and it is scattered in Wales in places where there are suitable calcareous subdtrates. Where it does occur it is often rather local and uncommon. In West Glamorgan it is virtually confined to limestone-rich sites along the south Gower coast. Sporophytes are occasional.