What the Ashkenazic Rishonim Lacked

A while back I read an interesting article by R. Natan Slifkin about the Case of the Jumping Elephants. In that article, R. Slifkin argued that the Ashkenazic Tosafists probably did not know how elephants looked like and therefore Tosafot to BT T. Kiddushin 26a made the mistake of maintaining that elephants can jump on all four legs. R. Slifkin writes that he got some angry feedback about his seemingly controversial idea, but he backs up his opinion with those of the Chatam Sofer on Niddah 18a who writes that Rashi's and Tosafot's description of the female anatomy does not match reality, and the Malbim who dismisses the Rishonim's opinion on the firmament due to it being unscientific.

The same issue was raised again a few years later by R. Slifkin in his discussion of the Kezayis. In his essay "The Evolution of the Olive", R. Slifkin asserts, based on historical evidence which includes testimony of Rishonim themselves, that Ashkenazic Rishonim generally never saw an olive in their lives.

Recently I came across another such instance where an Ashkenazic Rishon is accused of erring due to not having seen the subject-matter at hand. R. Yaakov son of the Rosh writes in his monumental work "Arba'ah Turim" (Tur OC §202) that since sugarcanes are mostly grown to extract their juice for sugar production but not for eating the cane itself because that is inedible and  therefore the appropriate brakhah on sugar would be Bore Pri Ha'etz. But R. Yosef Karo in his Kesef Mishna (Brakhot 8:5) comments on the Tur's words - and the Magen Avraham (OC  §202:13) cites the words of the Kesef Mishna approvingly - as follows:

ואני אומר שאילו היו קנים הללו נמצאים בארצו של הטור לא היה טוען כן. שבמקום שנמצאים מוכרים מהם לאלפים ולרבבות למצוץ אותם.

And I say, were these canes sold in the land of the Tur, he wouldn't have said so. Because in the places where they are found, they are sold in the thousands and ten thousand to be sucked.

Sugarcanes are usually grown in tropical regions (as per Wikipedia) The Tur claimed that the canes are inedible, but R. Karo says (as does -l'havdil- Wikipedia) that in the places where sugarcanes are grown they are regularly eaten. The Tur just never saw a sugarcane in his life.