Last fall, I found a mystery bean in a row of Contenders. The Contenders had been packaged and sold at a local farm supply. Well, Contender is white seeded and has a sprawling growth habit. This one plant was very compact and upright with small flat pods - and tiny black seeds. I am pretty sure I would have noticed a black seed when planting, but didn't. I ended up saving the seed from that one plant, which produced about a hundred seeds. This year, I planted a small row and found: 65+ days to maturity, 3" to 3.5" pods held close to the stalk, all have strings. We haven't eaten any yet.