A shrub, Ribes nigrum, that produces small, very dark purple, edible berries.
1993, R. D. Davidson, 19: The vegetation of Lough Neagh wetlands, R.B. Wood, R.V. Smith (editors), Lough Neagh: The Ecology of a Multipurpose Water Resource, Monographae Biologicae: Volume 69, page 487,
Blackcurrant (Ribes nigrum) and guelder rose (Viburnum opulus) are frequent but alder buckthorn (Frangula alnus) a common constituent of East Anglian carr is very rare.