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. On beaches with associated sand dune systems, strandlines can be the first phase of dune formation, when the strandline plants trap sand and start the process of building small hummocks in front of the foredunes.