About Vavilov, my bad, it was Petr Zhukovsky, don’t know why I confused them.
Zhukovsky wrote a monograph “Cultivated plants and their relatives” 2nd edition 1964 about this issue. He says that Cassela was right.

This information about Zhukovsky taken from book Guliaev V. I. “Pre-Columbian voyage to America: Myths and Reality” chapter 4.

Internet version of the book. You can use google translate. (http://mesoamerica.narod.ru/precolumb_sail4.html)

(there is no English version about him in Wiki, but you can use Google translate)
http://ru.wikipedia.org/wiki/%D0%96%...B2%D0%B8%D1%87

The hypothetical routes, actually were used by Columbus during his third trip. Anyway, both Columbus and ancient used wind and currents, that existed in both time frames, and as far as we know, by 3rd AD Romans had very good ships, that theoretically could survive the transoceanic journey.

About crew. Santa María also had 40 men crew, and they made transatlantic journey. But they managed to survive. And I don’t know if Romans used slaves on their ships, speaking about morale controle.

I was speaking about Scipio Aemilianus not Polybios. Guliaev argues that he reached modern Senegal.

If Europe has sagas, then indigenous peoples of America – tales about white beard people coming on the boat.

What coins etc?

In 1933 in Aztec tomb dated 13-15 centuries AD was found head of Roman sculpture dated 2 century AD. (Garcia Payon J. Una cabecita de barro, de extraña fisionomia // Boletin del Instituto Nacional de Antropologia e Historia. — México, 1961. — № 6. — P. 1—2.)

Hellen statues, Roman terracotta Venus (Romans in the Americas // Katunob. — Vol. П. — № 2. — Carbondale, Illinois, 1961. — P. 12; Gaddis V. H. American Indian Myths and Mysteries. — Pennsylvania, 1977. — P. 102.)

Venezuela – roman coins dated 4 century AD. (Romans in the Americas // Katunob. — Vol. П. — № 2. — Carbondale, Illinois, 1961. — P. 12; Gaddis V. H. American Indian Myths and Mysteries. — Pennsylvania, 1977. — P. 102.)
If some stuff belongs to collections, why only Roman stuff lost? Where are missing Egyptian, Arabian artifacts? Why the collections consist only from one item?