The following list of NEW WORLD flora incl.
flowers: 
Corn, Potato, Tomato, Bell Pepper, Chili Pepper,
Vanilla, Tobacco, Beans, Pumpkin, Cassava Root,
Avocado, Peanut, Pecan , Cashew, Pineapple,
Blueberry, Sunflower, Petunia, Dahlia, Marigold,
Quinine, Wild Rice, Cacao (Chocolate), Gourds, And
Squash.

With the obvious [paleo] disdain toward corn and
potatoes - there are many on this list which ARE
staples among paleo WOE followers... blueberries,
avocado, pecans, pumpkin and squashes peppers,
tomatoes, chilies, vanilla etc. never get the
"have we had enough time to adapt to eating these"
scrutiny that potatoes are meted.  

What of foods which originated in Australia like
Macadamia nuts? - Never heard one bad word about
them on any paleo list, book or website.

Citrus fruits were introduced to Italy by the
crusaders in the 11th century. is this long enough
for Europeans to have adapted to eating them?

Why then single out potatoes when there's a host
of other foods one could object to on grounds of
perceived maladaptation?  

Dedy

[Jim] Let's just assume those indigenous groups of
Central and South America who did eat them (not
all groups did) had time to adapt to their
consumption, Dedy.  What percentage of the world's
population are we talking about here?   How many
people are 100% descended from those groups?