Curtis Clark jcclark at CSUPOMONA.EDU
Fri Oct 17 07:48:00 CDT 1997

At 11:35 AM 10/17/97 +0100, Paul Goetghebeur wrote:
>During the preparation of a teaching session I came across the
>Lignophytes (progymnosperms + seed plants).
>However no description nor characterisation nor synapomorphies
>accompanying that name.
>I am interested in tracing back the origin of the name
>- published by who ?  where ?
>- in particular the "ligno" is something that is vexing me.

"Ligno" refers to "seed plant woodiness", with a single cambium
producing secondary xylem and phloem both. This is (I have read)
also found in progymnosperms, and would be synapommorphy #1.

Synapomorphy #2 is presence of a true eustele. This is
problematic, because part of the diagnosis of a eustele (as
distinct from a siphonostele) is the way in which it forms,
something that can't be directly oberved in fossils (I'm getting
out of my area here).

Sorry, I don't have at hand any literature references.

Curtis Clark
Biological Sciences Department             Voice: (909) 869-4062
California State Polytechnic University      FAX: (909) 869-4078
Pomona CA 91768-4032  USA                  jcclark at

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