Re: Limits of Kinds - Isoetes

Arthur V. Chadwick (
Sun, 16 Nov 1997 15:15:47 -0800

At 03:13 PM 11/13/97 -0600, Joel wrote:
>This may not be all that surprising though. Isoetes has a highly reduced
>vegatative morphology which such that any two species of the 150 species
>world wide would be difficult to tell apart from one another based on
>leaves, roots, or corm structure alone. The few definitive charaters
>involve the sporangia and spores.

Then a paragraph later...

>Some characters remained virtually
>unchanged over 200 million years while other exhibit a wide degree of
>change over time.

and later...

>Note also that lack of morphology change does not mean there is a lack of
>genetic change over time. Morphology and underlying genetic change are not
>always tightly correlated.

What exactly do you mean by "a wide degree of change over time"????