equisetum

[David R. Hershey]

Foster and Gifford's text Comparative Morphology of Vascular Plants (1974,
Freeman) uses Sphenopsida under which are included four orders. Three are
fully extinct: Hyeniales, Sphenophyllales, and Calamitales. Equisetales
included the living Equisteum and extinct genus Equisetites. The famous 
recreations of carboniferous swamps that often appear in botany texts 
usually include giant horsetails from the genera Calamites. 

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David R. Hershey
					
Snail mail: 6700 Belcrest Road #112, Hyattsville, MD 20782-1340

Adjunct Professor, Biology/Horticulture Department
Prince George's Community College, Largo, MD 20772-2199

Email: dh321 at pgstumail.pg.cc.md.us
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On 26 Nov 1996, Tianna Alain Kennedy wrote:

> Hello,
> 	Through the course of a class discussion on the subject of ferns
> and fern allies, a fellow student posed an interesting question that no
> one was able to answer.  I was wondering if, perhaps, one one you might be
> able to?
> 
> 	The question is whether there were sphenophyta that were not
> equisetum that may be extinct now, or whether sphenophyta have always been
> equisetum? 
> 
> 	Any takers?
> 
>