Monday, May 9, 2011

Pollination season

   Pecan pollen is starting to shed and pistillate flowers are in full view. In the photo at right, you can see a cluster of female pecan flowers growing a the tip of a new shoot. Female flowers are not very showy.  You can see the reddish stigmatal surface sitting on top of four leafy bracks. Below the bracks is the ovary. There are four female flowers in this cluster.
    The reddish color and presence of stigmatal fluid indicates this cluster of pistillate flowers is ready to receive wind blown pollen. The stigmas of pecan pistillate flowers can range in color from green to orange to deep red.
   The male flowers or catkins of pecan are also ripening and starting to shed pollen. In the photo at right, you will note that the catkins are actually made up of a long series of sack-like structures held under a leafy bracts. As the catkins mature, the pollen sacks grow larger and start to take on a yellowish color. During periods of low humidity, fully mature pollen sacks burst open releasing millions of pollen grains into the air. The pollen is transferred by wind to the receptive stigmas of pistillate flowers.
    Once all the pollen is shed, catkins turn brown and fall from the tree.