Formally, the UK is divided between England, Scotland, Wales, and Northern Ireland. Cornwall exists but is considered part of England now, as the Cornish language and culture was mostly replaced by the English more than two hundred years ago. Poor, poor Cornwall.
I'm personally interested in seeing how Plaid Cymru goes regardless of Scotland's independence referendum, as they are both the primary Welsh independence party and a Green party. I think the UK could last without Scotland, but if Wales splits too there will be very little holding England and Northern Ireland together. Cornwall might even get in on the action by then.
Plaid is less of a Green aprty, and more loyal to its roots - its heartlands are the rural north Wales counties of Gwynedd and Anglesea, where agriculture is king. Over time this has morphed into an understanding that our best natural resources all depend on our geography in one way or another (be it coastal resources, water, wind etc...).
I vote Plaid, but then I do live in one of the aforementioned counties which is a safe seat for them both in the Senedd and in Westminster. They have a track record of focussing on locally important issues, which works less well in the more densly populated south Wales industrial corridor where they are a distant second. The Tories and LibDems are literally knowhere down south, often polling below the Communist party and the BNP. Let that hit home a second. The Tories are less popular than a bunch of racist bigots in some south Wales electoral wards. Labour holds sway there (save for Cardiff city centre with its large student population voting Liberal) and probably always will thanks to the industrial heritage, unless Plaid make a big push for independance which hits home. Interestingly there is little to no talk of a push for an independance vote here - I suspect people in power who would like one to happen are waiting to see how Scotland goes before either wanting one of our own, or keeping it off the table to a more opportune moment.