Plaid Cymru – Party of Wales. Plaid, as they are commonly known, are Wales nationalist party.
Unlike the SNP, Plaid have always been less keen on Welsh independence and have actually only tended to promote it quite recently. In reality it is truer to think of Plaid as a Welsh language party (though the party has attempted to move away from this view in recent years).
The party enjoys close relations with its Scottish equivalent, the SNP.
Plaid tends to lean to the left of Welsh Labour (which is really saying something!) backing policies such as a maximum salary.
Plaid has seen its vote squeezed in recent years, and is in danger of losing its representation in the European Parliament this year.
The party is broadly pro-European.
It sits in the European Free Alliance grouping in the European Parliament. It has a below average loyalty to the Greens/EFA group at 95.6% though this is still notably higher than the SNP.