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Redbud (Cercis) - Some results - and Request for Seed collections

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  • Sam Droege
    All: We have followed up on the previous correspondence about looking at Redbud tree seed set to gain understanding about variation in pollination rates. We
    Message 1 of 1 , Nov 19 7:37 AM


    We have followed up on the previous correspondence about looking at Redbud tree seed set to gain understanding about variation in pollination rates.  We have been in contact with Isaac Park who is looking at Cercis ecology and historical bloom patterns and talked about some general ideas and ways of evaluating the data.

    In that regard Sarah Fisher (super intern) played around with some data from a few trees in the area.

    Attached is a pdf with the results (sorry about the formatting it was originally meant only for Isaac's eyes, but some of you may be interested).

    Bottom line is that with measured several hundred seed pods on 4 trees in a small suburban wooded yard and found that the average number of ovules in each tree was:


    Ovules, being locations within the pod that COULD  have had a seed.

    The average number of seeds was:


    The proportion of missing seeds in each ovule is:  


    We looked at sets of 15 pods in each of the 8 primary compass directions and as you can see in the table in the attached file there are indications of a tree effect in terms of proportional seed set.  

    We also gathered information on an additional 3 trees in the DC area (we have more to go) and found similar seed set.


    Here is where you come in.

    So, we would be interested in seeing what seed set was like elsewhere in the country (is it similar to the above or are there places where it is very low or very high).  Redbuds still mostly have their pods on their trees at this point, so if you have a tree nearby and want to contribute here is all you need to do:

    1.  Choose a branch as close as possible to head height for you.
    2.  Pull the first 20 seed pods from that branch starting at the tip and working your way back.
    3.  Include both the long and short pods
    4.  Open up each pod and count the number of ovules (the place where a seed should be...this should be obvious) and the number of seeds and email that information back to:

    Sam Droege

    Here is a reasonable format.

    Name:  Jane Treehugger
    Location:  3 miles east of the interesection or road 334 and 47 in West Mills, KY on highway 47
    (optional...you could send us a lat/long)
    Height:  About 22 feet
    Habitat:  Along the roadside
    Overstory:  No overstory...in the open

    Pod        Ovules        Seeds
    1        4        4
    2        6        5
    3        5        5
    4        5        4

    If anything interesting shows up we might expand this ... but for now we just want some simple seed set information.

    Planted or wild trees are both fine.

    Thanks all.

    Alternatively, you can send the pods to us.


    Sam Droege  sdroege@...                      
    w 301-497-5840 h 301-390-7759 fax 301-497-5624
    USGS Patuxent Wildlife Research Center
    BARC-EAST, BLDG 308, RM 124 10300 Balt. Ave., Beltsville, MD  20705

    If trees could scream, would we be so cavalier about cutting them down?
    We might, if they screamed all the time, for no good reason.
          -   Jack Handey

    P Bees are not optional.
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