Mutation is adaptation to its environment, even when the environment is temporary. Mutation occurs at the cellular level and the mutation continues with the creation of future cells. Sometimes the mutation is not very visible until many more cells have developed. It takes many years to develop a hosta that is going through a mutation.
Chemicals in the environment cause mutation. Farmers spray their crops, chemicals escape airborne or through the water way, and eventually land on other plants.
The sun causes a lot of mutation the same way that it causes discoloration on our skin, temporary or permanent. The sun also causes cancer which alters cells causing disfiguration or death. The same way the sun mutates hostas causing a different appearance. Some are attractive and those are marketed, while others are ugly and the latter are herbicide.
About 80% of hostas, mostly variegated, on the market are mutants. Other are seedlings, and a miniscule amount are species.
I hope I have explained this clearly.
