Posted: 20/07/2014 at 19:43
That's the male flower - it will soon develop pollen. Further down on the stem the beginnings of a cob or two will form and you'll see silky tassels emerging from the top of the cob. They are the female flower.
When the breeze blows the pollen from the male flowers will fall onto the tassels of the female flowers - this will fertilize the female flowers and produce your lovely juicy cob. When the silky tassels have turned dark brown (looking a bit like loose tobacco) your corn on the cob is ready to eat
By the way, they need plenty of water at this stage - keep the soil nice and moist.