15 November 2016
I let these grow, and about a month later realized that they were not zucchini. The two looked more like watermelon or cantaloupe vines. As the season turned to fall, a few fuzzy green balls appeared, about the size of baseballs. The wrinkled netting on the surface identified them as cantaloupe. Strangely, the netting surface covered only one half of the small fruit.
Some seeds from the compost that I used around the tomato plants sprouted, and the compost did have cantaloupe. I have had tomato seeds sprout from compost, but never cantaloupe. The plants were most likely some parent of a hybrid bred for the stores.