seeds

Kathleen Archer Kathleen.Archer at MAIL.CC.TRINCOLL.EDU
Fri Mar 20 15:48:23 EST 1998


Colleagues,
I'm teaching a course which surveys the plant kingdom, and I have taken an
evolutionary approach.  Coming up in 2 weeks I will be introducing the
concept of the seed, and I have been thinking about an exercise which will
illustrate to the students all the different components of the seed:
integument, megasporangium (nucellus), embryo, etc.  The 2 parts that I
think might be hard to show in a real specimen are the integument and the
nucellus (or remnant thereof) since in many seeds the nucellus is long gone
by the time the seed is mature.  I know in some seeds the seed coat has an
inner and outer layer which may separate but are still derived from
integument and I don't want to be inaccurate and call the inner layer
nucellus if in fact it is not.  I'm trying to find a seed where it is known
that the layer within the seed coat is in fact nucellar in origin.  

I wonder if anyone can recommend a seed which could be dissected to show
clearly and distinctly both the integument and the remnant of the nucellus?
 Something large and relatively easy to come by would be great.
Thanks for any help,
Kathleen Archer



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