Well, there is no doubt that mutations happen naturaly, but one can double the chromosomes of a plant in tissue culture using a chemical called colchicine. Its used in orchids all the time to make the plants with the label 4N. N represents the halfploid number. Everything is normaly 2N. When they have double chromosomes they are called 4N. The chemical inhibits the cells from splitting during mitosis, but they still double thier chromosomes. Then the chemical is removed and they start deviding like normal only they now have double chromosomes. Most 4N orchids are larger then thier 2N parents. As with orchids when you start getting into hybred you can have two hybred look almost identical but made with 2 different species parents. Thats why its so hard to identify a NoID hybred orchid. Amature growers don't go try to find or use colchicine unless you have expreance. It has a MSDS sheet a mile long with some nasty side effects. Its also used to treat gout.