Couldn't a genetic comparison give us an estimate of how long ago the 2 lines split?
And also whether it was from a single plant, or many?
I could see how a bird can pick seeds of a cactus and fly between continents, releasing a seed. The other similar, and bigger in my view, evolutionary puzzle is fresh water seals of Lake Baikal in Russia. Thousands of miles away from the sea shore, they are the only fresh water seals in the world. How they got there is a mystery. https://en.m.wikipedia.org/wiki/Baikal_seal
"But today, as crossing borders becomes ever more fraught, it’s worth remembering that with the right support, even a humble epiphyte can make it pretty far."
This hurts right in the realities.
Right were it hurts most.
its sad that even an article about cactus can't remain apolitical.
'eh I thought that way about it at first, too. But I decided to take it in stride.
Why? Cactus article writers can be frustrated with today's insane politics too!
As long as we've wandered this far into the bushes, I may as well get this out of my system: I really hate this kind of statement. Of course writers are allowed to feel whatever they like about politics. That's irrelevant to the question is whether it's appropriate to bring up politics in an entirely subject.
We have a special task force in the US to deal with plants entering from foreign countries. There are lots of rules on this and some plants and plants from some regions aren't allowed. So it's not really as free as suggested even pre Trump.