Consider the tumbleweed. Such a staple of the Western film genre that it has long since become a trope. Well, I only just learned that the plant is not native to the New World but is in fact an invasive species, that was accidentally introduced to the US by Russian immigrants in 1873: the flax seeds they were carrying had been contaminated with Russian thistle seeds (salsola tragus). Those quickly sprouted in the welcoming environment and spread throughout the drier regions of North America.
So, if you see tumbleweeds in a Western set before the 1870s, that's anachronistic. And if your TL has a POD before 1873, for all you know, it may not have tumbleweeds in the New World.
What other things have you come across that you didn't know where anachronistic until you looked them up?
So, if you see tumbleweeds in a Western set before the 1870s, that's anachronistic. And if your TL has a POD before 1873, for all you know, it may not have tumbleweeds in the New World.
What other things have you come across that you didn't know where anachronistic until you looked them up?