growth stages of Maize
In the first image, flowering occurs in the stage labeled "Pollination", which is when the male releases pollen and the female accepts pollen.  It give the time as 56-63 days after emergence, but note the asterisk ("*"); the footnote for it says their given times vary by "growth class" (such as "early" or "late"), indicating that these numbers are just a guide and actual times will vary by the cultivar (breeding strain) selected.