Old world beans
Lupines are also in legume family with beans and some lupines have seeds that are edible if they are prepared properly. Mine are just ornamental.
The tale of Jack and the beanstalk has ancient origins, which means beans have been on people's minds for a long time. Dried beans are one of the oldest domesticated crops and provide a good amount of protein while improving the soil. They're also easy to grow, to thresh and to store. But even in antiquity, not everyone was a fan – according to Rebecca Rupp in How Carrots Won the Trojan War Pythagorus's clan of vegetarians wouldn't eat beans because they believed that maybe, just maybe, people could be reincarnated as them. I'll assume that is just a story and carry on eating plenty of beans.
Edible beans are diverse – many of which can't be found at the local super market or even the hippy-est bulk store. They come with great names too like: tiger's eye, black night fall, lablab, Atawallpa's fingerprint, yellow-eye, ... and I could go on an on. What do they taste like? It seems the only way to try many of these is to grow them. From a seed saving point of view some bean types cross readily with other closely related types (i.e. those in the same family) and some don't. How many varieties in each family one can grow to save seeds can come down to how big your garden is.
I thought I would do a brief summary of the types of edible beans I've stumbled across starting with the ones that originate from the old world (I think), and I likely haven't come across all the edible types.
Broad Bean (Vicia faba) – also known as fava beans. These are the only bean that can be sewn in the fall and harvested the next year (assuming a relatively mild winter). This bean is native to northern Africa and southwest Asia. These were domesticated in neolithic times (i.e. When humans started farming using stone tools) in the eastern Mediterranean.
Chickpea (Cicer arietinum) – People have been eating chickpeas in Turkey from at least around 5000 BC (hummus has been popular a long time!). In ancient times this bean was grown all around the Mediterranean and in Ethiopia and introduced to India around 2000 BC.
Hyacinth Bean (Dolichos lablab) – Originally from India, this one was grown in the Biodome 2 experiment, I have their cookbook and was thinking of growing this one, however I'm likely too far north to get a crop. Hyacinth Beans are often grown as an ornamental vine.
Pigeon Pea (Cajanus cajan) – this is a perennial shrub commonly grown in India, probably also originally from there. I can only grow this as a house plant and I have one going, if it thrives I'll take some pictures.
Soy Bean (Glycine max) – an ancient Chinese crop that can be made into all sorts of tasty things like tofu, tempeh and soy milk.
Lentil (Lens culinaris) – one of the most ancient crops, there is evidence these have been grown in the eastern Mediterranean since at least 6700 BC. Their name relates back to optical lenses due to the shape of some lentil varieties. The big advantage to lentils is they cook up relatively quickly.
Cow pea (Vigna unguiculata), this family includes the blackeye pea and yardlong beans and originates from Ethiopia around 4000-3000 BC. Currently this bean is grown extensively in India and west Africa. And is the traditional bean of the American south. This bean doesn't need to be soaked before cooking, speeding up its preparation.
I've skipped the peanut – another tasty legume that has become almost ubiquitous. And, coffee beans are not beans at all, instead they are the seed of a tropical fruit. Next up is the new world beans...
* my main reference was The Random House Book of Vegetables by Roger Phillips and Martyn Rix