Topinambour would have been available in the middle ages. Confusion with potato by the modern reader is understandable, as a topinambour does look similar to a potato, and some German dialects (e.g. Swiss dialects) name potatoes "Erdapfel".
> Topinambour would have been available in the middle ages.
No, Helianthus tuberosus [1] aka "topinambur" is Jerusalem artichoke which would not have been available at the time. It's a New World crop just like the potato.
We're talking about a book written in 1462, before the Columbian exchange. The plant wasn't introduced to Europe until the early 17th century.
Topinambour would have been available in the middle ages. Confusion with potato by the modern reader is understandable, as a topinambour does look similar to a potato, and some German dialects (e.g. Swiss dialects) name potatoes "Erdapfel".