Re: Limits of Kinds - Ginkgo

Arthur V. Chadwick (
Sun, 16 Nov 1997 14:33:00 -0800

At 08:44 AM 11/11/97 -0600, Glenn wrote:

>I would not deny that Ginkgo is
>probably the slowest evolving of the living fossils. But I would deny that
>there are no differences. I would refer you to the rest of the paragraph
>that you cited above which outlines some of the differences between the
>various species.

>I think we could agree on this. And I will re-iterate, the Ginkgo is the
>most similar of ancient to modern examples of living fossils.

There are few differences between most extant genera of plants and their
predecessors from the Upper Mesozoic. I mentioned earlier a report by
Tidwell of Acer (maple) from the Dakota Sandstone (reported by him at the
time to be Upper Jurassic at the locality in question) which included
flowers, fruit and leaves and pollen, which could easily be placed in the
genus by anyone who saw them. This example could be repeated for many
genera of flowering plants, which from their first appearance as fossils
are handily assignable to extant genera. Of course there are also form
genera that do not belong in any modern genus, some of which can be
assigned to modern families and some of which cannot. Unlike Ginkgo,
however, these do not go back to the Paleozoic.