From: Ben Pittenger (benpittenger@earthlink.net)
Date: Tue Apr 23 2002 - 22:04:22 PDT
Date: Tue, 23 Apr 2002 22:04:22 -0700 From: Ben Pittenger<benpittenger@earthlink.net> Subject: Botany help - cotyledon vs endosperm? Message-ID: <Springmail.0994.1019624662.0.01840600@webmail.pas.earthlink.net>
So who can clear this up for me? I am working with my 7th graders on bean sprouts, but I have begun to question my memory on the definitions of 'cotyledon' and 'endosperm.' My memory was that a cotyledon is an initial leaf that forms from the embryo in the bean/seed (hence the terms monocotyledon and dicotyledon), and that the endosperm is the fleshy part of the bean or seed that provides nourishment as the embryo grows and emerges from the bean/seed. Each botanical dictionary that I have found defines cotyledon as a seed-leaf or embryonic leaf.
However, I have also found several sources (including one picture in our text - not that our text is definitive!) that label the two fleshy regions within the bean as 'cotyledons.' Some of the internet sites appear otherwise quite reliable, and since this reference has shown up in multiple places, I wonder if the term cotyledon has been expanded to include these fleshy regions. Or is there something about beans that gives the term cotyledon a broader definition in this case?
If you have input, please help!
Thanks,
Ben
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