The first phase of dune formation is the development of a strandline to begin trapping sand and start the process of building small hummocks. Strandlines tend to ephemeral in nature, there one summer and not the next, and tend to comprise annual plant species – that flourish in seasons when weather patterns and tides are suitable. Two of the commoner species of strandline plant in Wales are sea rocket (Cakile maritima) and sandwort (Honkenya peploides) often accompanied by several species of orache (Atriplex spp.) among others.