fieldmuseumphotoarchives:

Sweet Potato (Ipomoea batatas) flower model. The sweet potato is only distantly related to the potato (Solanum tuberosum)
&copy; The Field Museum, B81971.
Sweet Potato enlarged flower. Ipomoea batatas, Convolvulaceae. Plant model.
8x10 negative
3/1/1964&nbsp;

It is more closely related to the morning glory, Ipomea purpurea, though, honestly, the whole genus is fascinating!  ~AR