Tree Flowers (and fruits) 

Norway maple, Acer platanoides is a hardy European tree widely planted as a street and lawn tree. It is increasingly unpopular because of it invasive tendencies, being seen more and more in woodlands where it doesn't belong. Norway maple flowers profusely in mid-spring. Leaves and flowers emerge simultaneously. Entire trees look like giant yellow pom-poms.  


Norway maple flowers, colorful and conspicuous, are visited by nectar-seeking bees.


This species is variously reported as monoecious, i.e., producing unisexual flower with both sexes on the same tree, or dioecious (separate male and female individuals). Examining several trees flowering over a 2-week period only made things more confusing. Flowers with a well-developed pistil also bear stamens, but they are distinctly shorter than the stamens of obviously male flowers that lack a functional pistil.  And it seemed that some trees that produced female flowers early in the blooming period shifted over to solely staminate ones later in the season (or was it the other way around?). This aspect of the species -- its "breeding system" --requires closer monitoring.