Today I learned that a corn cob with an odd number of rows is more unusual than a four leaf clover. There have even been instances where corn with an odd number of rows has been reported in the news due to its rarity. If you've ever counted the kernels on your corn and spotted an uneven row, consider yourself lucky.
Carroll Daily Times – Sep 14, 1949
"Corn always has an even number of rows on each ear. A corn ear is actually an inflorescence that produces nearly 1,000 female flowers. These flowers, or potential kernels, are arranged in an even number of rows (usually from 8 to about 22 rows). Row number is always an even number because corn spikelets are borne in pairs, and each spikelet produces two florets: one fertile and one sterile."