Bietola da coste is Swiss chard (or 'leaf's beet'). It's a classic ingredient in Liguria's famous Easter dish, Torta Pasqualina. In some places you might see it called svizzero.
Italian chard, which doesn't have the same thick stems, is bieta. (sometimes called bietola a coste fine)
Bietola da orto is another word for beet, barbabietola. Chard, really, is only a beet that has been bred to emphasize the leaf and not the root.
Images by: ALex