I was quietly waiting for this little issue to come up.
All beans are legumes but not all legumes are beans. Beans, peas, lentils, chickpeas, and peanuts are all legumes. Moong beans are classified as a bean - but having said that, 'bean' is a rather loose term:
According to the
Penguin Companion to Food, bean is a “term loosely applied to any legume whose seeds or pods are eaten, not classed separately as a pea or lentil.” Beans traditionally were in the genus
Phaseolus, but now some of the species, including the black-eyed pea, are in the genus
Vigna. Peas are in the genus
Pisum.
However, despite what the Penguin Companion to Food says, some sources such as the USDA do not classify green beans as a bean. How is that for confusing?
Beans and peas are unique foods | ChooseMyPlate
Given the 'looseness' of the term, I reckon it has to be up the the judge for this challenge to decide what qualifies.