David Haas dhaas at CHI1.UNCFSU.EDU
Thu Mar 14 15:15:18 EST 1996

Jim Perry said:>> 
> At the risk of sending something that most of us might know...

There's no risk here.   I 've always thought that fibers were more 
specialized and evolved from tracheids.   Also I thought that the 
first vascular plants had tracheids not fibers.  Please set me 
straight.  What about Rhinia and Cooksonia sp.  are there now fossils 
that  pre date these early plants.    I took Paleo-bot  in the 
Paleozoic ! 

> The evolution of xylem tracheids is presumed to have occurred as a result of 
> modification of fibers, and subsequent to that, vessel members to have evolved 
> from tracheids. Inasmuch as early land plants were likely thallose, and were 
> in fact probably more accurately described as amphibious, any development of 

Dave Haas                               
Department of Natural Sciences    
Fayetteville State University    
Fayetteville, NC 28303           

"More than any other time in history, mankind faces a crossroads. One 
path leads to despair and utter hopelessness.  The other, to total 
extinction.  Let us pray we have the wisdom to choose correctly." - 
Allen Konigsberg.

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