This image is slightly misleading, male preflowers will always sit on a tiny stalk which can clearly be seen as soon as male preflowers are visible
female flowers will appear to just grow out of the branch with no stalk underneath the calyx
it is this tiny stalk that is the most clear visible sign to determine sex in early stages of preflower
since female flowers can sometimes be visible before any pistil have emerged from them
also sometimes pistils are seen first before the calyx is large enough to be seen with the naked eye
the major difference in appearance is the stalk that the male flower sits on
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