Gastridium ventricosum Nit-grass

A winter annual (occasionally summer annual) grass which occurs as native populations on south-facing  slopes overlying chalk or limestone. It is a rare Mediterranean-Atlantic species, now more or less confined to parts of southwestern Britain and the Channel Islands. It was once an occasional weed lof cornfields and is sometimes still recorded, albeit rarely, as a casual alien introduced in grain or wool. Its occurrence on the south Gower cliffs, where it is undoubtedly native, is significant and it was the subject of a thorough and notable study by Rosemary John in the 1980s and 1990s. Rosemary's observations showed that population sizes vary greatly in size from year to year and sometimes appear to be absent altogether. The availability of open disturbed areas and reduction of competition is very important to its sustained success and numbers of plants were higher when competitors were suptressed after periods of drought or fire. The size of Gower populations is positively correlated with the incidence of gorse burning cycles and it appears to maintain a large seed bank in the soil which remains viable for several years.

Native