Wednesday, March 18, 2015
Foxtail’s Filters
Take a close look at meadow foxtail grass’s flower spikes in spring and you’ll find that the youngest have just begun to produce their feathery white stigmas (bottom photo), while more advanced flower spikes are releasing pollen from their dangling stamens (second up from the bottom). Under the microscope the stigmas are revealed at feathery combs of transparent cells whose job is to filter out the airborne pollen (third photo from bottom, x100). Once they’ve trapped a pollen grain it germinates, producing a pollen tube that grows down through the stigma cells (top photo x400), carrying the male cells down to the egg cells in the flower ovary, where they fuse together and begin the process of seed formation. In the top photo you can see the pollen tube emerging from the germinating spherical pollen grain and growing down through a branch of the feathery stigma. Theres more on meadow foxtail grass on my other blog at http://cabinetofcuriosities-greenfingers.blogspot.com/
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