Sweet potatoes are morning glories, or morning glories are sweet potatoes. That's because sweet potatoes are Ipomoea batatas, in the genus Ipomoea with all the morning glories. If you've grown sweet potatoes, you will have seen the tubular blue flower, very like weedy morning glories such as Ipomoea hederacea and Ipomoea purpurea.
sweet potatoes, Ipomoea batatas |