I don’t think hybridization presupposes the existence of two species. Hybrid corn or rose strains are produced in great quantities and they are still corn or roses. I’ve read a lot of rose catalogs and spent time in Iowa and I never had the impression that either corn or roses were different species. The same cold be said about dogs.
All dogs are one species, and were selectively bred over a long period of time from their wild cousins, the wolf (and wolf-dogs are not uncommon). All corn can cross with all other corn, and was wildcrafted from a single wild species. Roses are a different story -- they are related to lots of edible species, but while I've heard of plum/apricot crosses, I've never heard of a rose/peach cross.