actually, for a spotted multiflora or a tilia multiflora it is 1/3

what i was trying to say (and not very clearly ) was if you "mutate a multiflora", meaning a "xxx multiflora" to a "xxx yyy", the chance of yyy being ridgeball is 50/50.

if you use the save/restore game (see plant tycoon guide for how this is done) you can increase your odds of mutating the plant to what you want from 25% to 100%