Define Epigeal and Hypogeal

J.E. Shields
Mon, 04 Jan 2010 12:39:05 PST
Hi sll,

"Germination" seems clear enough -- when the embryo starts to elongate 
along its axis and proceeds to grow out of the seed.

Here is definition of "germination" in

"The stage in which a germ or a living thing starts to sprout, grow and 
develop. ...
Germination in plants is the process by which a dormant seed begins to 
sprout and grow into a seedling under the right growing conditions."

Jim McKenny has it right -- applying the general definition to specific 
cases forces  modifications to fit circumstances.  How to twist the dicot 
definitions of epigeal and hypogeal to fit monocots is the task at hand.

People do tend to confuse the first above-ground appearance of a green 
shoot with germination of a seed.  This is not a correct technical use of 
the term "germination."  For seeds that germinate above ground or in petri 
dishes, the first appearance of the (white) radicle through the seed coat 
corresponds to true germination.  The same thing applies to germination 
below the surface of the ground.

Jim Shields

At 11:58 AM 1/4/2010 -0800, you wrote:

>The problem is the inclusion of 'germination'. The definition of hypogeal 
>and epigeal is clear.
>  T
> > Date: Mon, 4 Jan 2010 14:51:09 -0500
> > To:
> > From:
> > Subject: Re: [pbs] Define Epigeal and Hypogeal
> >
> > The problem with the simple definition -- cotyledons above ground after
> > germination vs. cotyledons below ground -- is that for many monocots, the
> > cotyledon stays inside the endosperm structure and that is where the seed
> > was -- above ground or buried, happenstance perhaps -- when the seed
> > germinated.
> >

Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344     or      toll-free 1-866-449-3344 in USA

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