Which of these is not a root vegetable?

Root vegetables are underground plant parts eaten by humans as food. Although botany distinguishes true roots (such as taproots and tuberous roots) from non-roots (such as bulbs, corms, rhizomes, and tubers, although some contain both hypocotyl and taproot tissue), the term "root vegetable" is applied to all these types in agricultural and culinary usage.

Many root vegetables keep well in root cellars, lasting several months. This is one way of storing food for use long after harvest, which is especially important in nontropical latitudes, where winter is traditionally a time of little to no harvesting. There are also season extension methods that can extend the harvest throughout the winter, mostly through the use of polytunnels.

All pumpkins are winter squash, mature fruit of certain species in the genus Cucurbita.