Sassafra Leaf Morph distribution

RossN at RossN at
Wed Dec 8 16:10:00 EST 1993

This has probably been stated before, but here goes. In my (non-scientific)
observations of maple and oak trees of eastern Canada, I have noted that the
more light a leaf sees the deeper the lobes on the leaf. Shaded leaves of a
mature maple are more "rounded" than leaves from the top of the same tree.
Could a similar phenomenom explain the lobes in the Sassafras tree?  Could
this be tested by shading selected branches on a tree at the beginning of a
growing season and compare with unshaded branches?  Just my two cents worth.
(If my statements appear naive, it's because they are)
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To: plant-biology at
From: deh at (Dave Harry)
Subject: Re: Sassafra Leaf Morph distribution
Date: 8 Dec 93 18:13:06 GMT
In article <kwestin1-071293164330 at> kwestin1
>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   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             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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