Answer: You raise an interesting question! If plants were to cross-pollinate, you wouldn't notice a flavor difference in the current crop, but if you were to save the seeds to plant the following year, you may end up with something quite different that you thought you were planting. Here's why: All vine crops belong to the Cucurbitaceae family, but only the pumpkins, squashes, and most gourds belong to the genus Cucurbita. However, cross-pollination will depend upon the species in this genus. Watermelon and citron both belong to the same genus (Citrullus) and therefore will cross-pollinate each other. Muskmelons and Casaba melons will cross, since they are both in the same genus (Cucumis) and also the same species (melo). Cucumbers belong to the genus Cucumis and thus will not pollinate with pumpkins, squashes, gourds and watermelons, since they are of a different genus. In addition, cucumbers will not cross with other melons of the same genus, since cucumbers belong to a different species known as sativus. So, you can safely plant cucumbers and watermelon in the same patch without worrying about either tasty "funny". On the other hand, if you plan to grow summer squashes and pumpkins, and if you decide to save the seeds from the fruits, you may end up with some oddball squash next year.
Hope this clarifies things for you!
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