Have you discovered a way to "prove" axioms? :^)
I wish ;)
Anyway, some things have to be taken as axiomatic, even by experts, and some things that might be provable to experts are not accessible to the rest of us. I have some math in my background, but not nearly enough to evaluate the validity of Andrew Wiles's proof of Fermat's theorem. If the mathematicians tell me it's proven, I don't have much choice but to accept what they say - for all intents and purposes, the statement "Fermat's last theorem is correct" is taken as axiomatic to me, if not to mathematicians. I have neither the tools nor the training to do otherwise, although the process is open in the sense that we can at least imagine me coming to have that knowledge. And if British botanists tell me that this plant is something never before seen, and most likely a brand-new species, what choice do I have but to accept that, too?
Maybe it'll turn out that this conclusion is wrong - it's happened before, as with that thing on flatworm speciation or whatever it was that we were talking about a few months ago. But with a few exceptions, none of us here can really do anything but wait for something resembling consensus to arise - we aren't in a position to do much but take their word for it. We all (hopefully) understand the process of scientific investigation, at least, and accept that the process is likely to eventually produce a correct result, so now we wait for that to happen.