I’ve been reading up a bit (as is my way) about our new flowering trees.  I thought the banana and papaya were pretty interesting, but the avocado takes interesting to a new level.  Avocados are known for producing many more flowers than fruit, as pollination is quite a complex matter.  Avocado flowers are the only flowers with separate male and female phases.  Each flower opens first as a female and then the next day as a male.  On top of this unusual feature, there are two types of avocado trees with different timing of the flowers: A-type trees open their female flowers in the morning and these flowers reopen as males in the afternoon. B-type trees open their female flowers in the afternoon and then their male flowers the following morning. Since fruiting requires cross-pollination, it helps to have both phases.  Confused? The full story is here at the University of California web site.  I highly recommend their stop motion film depicting the flower cycle.  Fascinating stuff!