Field of Science

Friday Fabulous Flower - pink powderpuffs


Darn such a busy week.  The good news is that a not too violent front delivered nearly 2 inches of rain overnight greatly helping replenish ground water.  Even still our water bill will be a frightful thing.  This week's FFF appears thanks to our neighbors who have this tree in their front yard.  Generally known as mimosa, it's actually Albizia julibrissin. A long-time ago introduction to North America it tends to be a bit invasive and weedy.  Like a lot of fast-growing trees it tends to die back a lot, often dying young, especially here near the northern limits of its cold hardiness (zone 5).  However it is a quite pretty thing and if you know your botany, you recognize the powderpuff flowers and doubly compound leaves as characteristic of a mimosoid legume.  It's fruits are many seeded pods and in warmer climates the germination rate is high.  Powderpuff flowers in general tend to use the stamens as the attractive floral feature.  In mimosas like this the "puff" is actually a whole inflorescence, a ball or hemisphere of flowers, each with flower only has 10 stamens but when clumped together the display is quite showy.  Sticking up among the stamens is a single pistil's style and stigma (whitish filaments sort of sticking out).  Many decades ago when TPP was interviewing for a job in the south, the department chair asked me what I could see as we drove along, "There's nothing there but mimosa trees and a cotton field," was my answer (northern boy passed that test).  

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