Picture posting is enabled for all :)
Frenchies self-pollinate, so no worries there. Runners are right sluts, and do it with any old pollen. I've more experience with broadies (don't like runners), and while they screw around merrily, if I plant two varieties at opposite ends of the plot, they don't hybridise that you'd notice. I haven't tried it with runners.
But I'm sure someone will be along shortly....... :)
I don't want to get into a big, boring lecture on taxonomy here but think I should clear up a couple of things.French, borlotti, pinto, wax, etc beans are not the same family, they are cultivars of the same species (Phaseolus vulgaris).Lima/butter beans (Phaseolus lunatus) and runner beans (Phaseolus coccineus) are in the same genus as French beans (Phaseolus).It is possible for species in the same genus to hybridise and there are many papers on hybridisation in Phaseolus, including the 'father' of genetics, Mendel.The above beans and broad/field beans (Vicia faba), and other legumes such as peas (Pisum sativum) are in the same family, Fabaceae.It is also possible for some species in the same family to hybridise, although it is less frequent and the offspring are usually sterile, as seen in cyprinid fish and equines.....Told you it was boring! ;D
We have grown cherokee beans for about 6 or 7 years now and we save our own seed.Every year we get some plants that produce a bean of the same size but flatter than the original and also more stringy. As soon as we see them we whip them out.Have also noticed that some of the saved beans are flatter and more straight edged than the original so this year have only sown the perfect ones.will let you know the outcome