In Peter Martyr's De orbe novo decades (Decades of the New World, 1511–25), he thrice compares axi to something he calls Caucasian pepper. The following excerpts are from the 1912 MacNutt English translation:
In First Decade, Book I (1912, p. 65):
rough-coated berries of different colours more pungent to the taste than Caucasian pepper
In Fifth Decade, Book IX (1912, p. 186):
Something may be said about the pepper gathered in the islands and on the continent. I mentioned pepper as growing in the forests; but it is not pepper, though it has the same strength and the flavour, and is just as much esteemed. The natives call it axi. It grows taller than a poppy, and the grains are gathered from this bush just as from a juniper or pine, although they are not so large. There are two varieties of these grains, five in the row; one of which is half a finger in length, and its taste is sharper and more biting than that of pepper; the other is round and has no more taste than pepper. Its bark, skin, and kernel have a hot flavour, but not very sharp. The third grain does not sting the tongue but is aromatic. When it is used there is no need of Caucasian pepper. The sweet pepper is called boniatum and the hot pepper is called carribe, meaning sharp and strong; for this same reason the cannibals are called Caribs, because they are strong.
In Seventh Decade, Book I (1912, pp. 250–1):
Our pepper, of which I sent a specimen to Ascanio Sforza, grows abundantly everywhere in this country, just like mallows and nettles at home. The islanders crush it and spread it on their bread, which they soak in water before eating. There are five varieties, and it is hotter to the taste than the pepper of Malabar or the Caucasus. Five grains of ours are equivalent to twenty of Malabar or Caucasian pepper, and seasoned with these five grains the juices of meats acquire more flavour than with twenty of the other. But such is human stupidity that whatever is difficult to obtain is always thought to be better.
Is it possible to grow pepper (Piper) in the Caucasus and was this ever done? If not, what is meant by Caucasian pepper here?