Just passing this on as something interesting from Native Seeds/Search. They do mail order.

Heirloom Chard Now Available Online and at the Store

We're excited about the marvelous Magdalena Acelgas, a family heirloom from Magdalena, Sonora. The seeds were donated by Jesus Garcia and grown out at the Mission Garden Project of Tucson. This variety has shorter stems than most modern chard varieties. It grows well in the winter and through the summer in the low desert. You can find it ONLINE and at the store, and we also hope to have plant starts in the upcoming Fall Plant Sale.