Those are all male flowers.
Seeds take 4-6 weeks to grow and mature after you pollinate the female flowers. For this reason, pollinate early, as soon as the female you intend breeding from has small tufts of white pistils, usually around 2-3 weeks after flowering begins. If you pollinate 4-10 lowest branches, this will give you 50-400 seeds.
Pollen can be mixed 50-50 with corn flour to extend it if you only have a limited amount. Use a small paint brush to apply the pollen and make sure there is no wind. After an hour you can spritz the excess pollen with plain water to kill it and this will prevent having many thousands of more seeds that you never intended. Remember too, if you breed with pollen taken from an hermaphrodite, the seeds will be hermaphrodites too. If the pollen is coming from a pure male (no female flowers present at all), the seeds will be regular seeds, with a 50-50 chance of being male or female, and will not be feminized. This is also the case if you were to use the pollen from an hermaphrodite, a 50-50 chance of being either male or female. Feminized seeds are made through a chemical mutation process, and not by using "normal" pollen, but a chemically reversed female plant that is genetically altered to grow male flowers.
Hope this helps,............
Organoman.