Let's put it this way. Just because we have zoos doesn't make those animals native. There is probably some threshold of self sustainance and propagation in the region to call it native, after many centuries I would presume.
Some of they definitely are. One of the most famous, Phoenix canariensis is endemic from Spanish Islands. The Mediterranean has also several native palms, and even ecosystems when palms are one of the dominant species. Chamaerops humilis, the palmito, is a small palm. Is a 100% legit European palm (and a fairly decent vegetable also that could fit perfectly in this list).
The GP may or not be suggesting that, but coconuts do migrate. Their physical structure enables that: a sealed capsule that can float, with rich nutrient density inside, and airtight, so due to all that, stays viable while it is carried across oceans from one country to another. And germinates and grows at the destination.
Read something to that effect somewhere, maybe in Wikipedia or similar.
Winds and tides and ocean currents and waves do the rest.
The plants that developed seed dispersal in micronesia are fascinating. It's a tough evolutionary nut to crack. Honestly though, I was making a holy grail joke ;^)
All of nature and natural mechanisms are fascinating. So much of math and science and beauty in it, as scientists and the lay public keep discovering.
Just today, sitting at a cafe outside a town, I saw something new to me: a small frog, just about one inch in length, sitting vertically on the low side wall of the cafe. I think it was actually climbing up the wall. At first I thought it was a large insect.
Then went closer and saw it was a frog. Took a photo of it.
Edit: If I can, I will post a link to that photo here. (Have some constraints for that at present.)
I didn't get the holy grail joke. Googling seems to show it is related to Monty Python shows, which I do not watch, Guido knows why :)