Why three cotyledon?

[Digeroo]

I have a sprout plant that had three cotyledons, thei has happened before and the pants do not usually thrive but this one is huge but otherwise looks normal.  Will it produce sprounts?

I actually had some beans last year and they produced four seedlings with three cotyledons and then all the subsequent sets of leaves were also in threes.

[Digeroo]

[davyw1]

Its not uncommon but plants that come like that tend to struggle i think you will find that the other plant that bore only two will grow about five times faster

[Robert_Brenchley]

I think it's probably a mutation, unless it's due to damage to the seed. This year I've got a pea with no chlorophyll, so its ghost white. Obviously that one won't thrive!