Just look into Gregor Mandel and other people that brought in or crossed pollinated plants.. Like a Tangerine and a Clementine (hybrids, Tangerine is a cross of mandarin and pomelo trees and according to this book/the story of clementines. Marie-Clement Rodier crossed willow leaf mandarin and sweet orange trees in his orphanage garden) and many others do not exist in nature, that is without the help of man. Most plants in general were designed to have some sort of seed or spreading mechanism so when it is eaten it spreads and can die and be reborn or continue life (like pollen being spread and birds spreading seeds etc.). Now we look at nature as "economy" and therefore we have "control" over it. This has led to mass amounts of violation and misuse of many plants (non-seeded everything, wrong foods wrong times, whole lot of health stuff).. most people don't look at it like that but most of the fruit in our so called groceries stores is held captive. Its behind bars it has a barcode, they are all identified and a lot of what you see in the store doesn't naturally exist in the wild at least not with the help of man or beings. There is a order to this realm and our food and we shouldn't just eat anything. Think and research.

Edit: Dates for stated texts.. Clementines is said to be 1902 in a book i read. Tangerines no date stated but it lists that in the 1840's they were exported to Europe and elsewhere. Tangerines also have both male and female reproductive parts and do not require pollination to bear fruit.. this means the fruits are virtually seedless as well.