Marsupella aquatica

A glossy, dark-green, dioicous leafy liverwort which forms patches on rocks and boulders that are permenantly irrigated by or submerged in water in upland streams and rivers or in the spray zones of waterfalls. It is regarded by some as just a variety of Marsupella emarginata and in some situations the distinction between both is not clear. Both species have notched leaves with the lateral margins distinctively recurved. However Marsupella aquatica tends to be a larger plant with a leaf notch that is less than one fifth of the length of the leaf. Its status and distribution is uncertain at national and local scales because many recorders find it difficult (or unnecessary) to differentiate specimens within the Marsupella emraginata agg. In West Galmorgan we have taken the view, in the field, that robust plants with shallow notches in markedly aquatic situations are Marsupella aquatica. Plants which fit that description are scattered in upland streams mostly in Neath Port Talbot. Sporophytes are frequent.