Introgressive hybridization is a well-accepted precept for some mechanisms of speciation. And
polyploidy can be part of the process, as well.
I'm sure that Nepenthes are also involved in the speciation process.
I remember, the very first time I saw wild
Drosera rotundifolia. It was adjacent to a little copse of evergreen trees, the copse of trees were facing south, towards the north shore of Lake Michigan, there on Michigan's upper peninsula. I stopped at this spot, because there was a clearing in the overgrowth, and a small sandy beach, where the lake was easily visible. This was while I was on my way to visit Big Manistique Lake, hoping I would see other CP at that lake. Anyway, I was standing, with my back to the trees, and facing the lake, there was a small sand dune between me and those trees. This created a small protected depression, and provided a little shade for the back of the dune and the depression. I was a little frustrated that I hadn't spotted any CP, yet, but just as I was giving up at this location, I turned towards the back side of the dune and Lake Michigan, preparing to climb out of the depression, when, out of the corner of my eye, I noticed that the back side of the dune top (the side facing north, towards the trees), was covered with
Drosera rotundifolia plants. These wild plants were the first ever
Drosera rotundifolia plants I had ever seen - they were, beautiful, and they immediately stopped me in my tracks. At that angle, they were a little backlit, and sparkled in the sunlight. As I examined them more closely, I was surprised to see that some had rabbit dung stuck on their leaves. Ahh, memories. That was in the late 1970's.