Sassafra Leaf Morph distribution

Dave Harry deh at s27w007.pswfs.gov
Wed Dec 8 13:13:06 EST 1993


In article <kwestin1-071293164330 at mac08.whartoncd.swarthmore.edu> kwestin1 writes:
>Two undergrads at Swarthmore College are looking at the distribution of
>three leaf morph shapes over a range of trees, species Sassafras albidum. 
>We've found a strong correlation between percent unlobed leaves and age -
>the older the entire tree (not just the branch), the more unlobed leaves it
>has.  A literature search has turned up very little and we're brainstormed
>out.  Any ideas, however wild, entertained!  Can _you_ think of a reason
>for the correlation?  Responses, questions sent to
>kwestin1 at cc.swarthmore.edu   Many thanks!

I can't speak to this specific problem, but there are many examples (some
published, even more observational or anecdotal) of developmental trends
in woody plants related to maturation.  One simple explanation might be
that leaves w/o lobes tend to be more frequent as trees mature
(which you've
already observed).  Age and maturation state are not perfectly correlated,
however.  Other examples of maturation-related phenomena include the
relative abundance of male vs female reproductive structures (on
monoecious species such as conifers), rooting ability, etc.  You might
check the literature on woody plants using search terms such as
maturation, juvenility, rejuvenation.  Two authors who come to mind are
Michael Greenwood and William J. Libby.  

Good luck!

David Harry                       Institute of Forest Genetics
deh at s27w007.pswfs.gov             USDA Forest Service, Pacific SW Station
Phone:  510/559-6439              PO Box 245
FAX:    510/559-6499              Berkeley, CA 94701

My failure to mention other authors is simply due to ignorance and
negligence, not to malicious intent.  :-)



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