what we call turnips in the US are apparently a different species than what we call rutabagas, which Europe calls Swede/neep/tumshie/etc. These were probably the first type of vegetable to be carved into spoopy lamps for Samhain and related fall festivities

at least that's what I've gathered from reading Wikipedia and the internet

US turnips are a lot softer and would probably be easier to carve but have less longevity (haven't tried myself)