any species reproduce only asexually?

David Hershey dh321 at excite.com
Tue Aug 6 20:50:26 EST 2002


Plants that cannot sexually reproduce at all are fairly rare.

There are some fern species, such as Vittaria appalachiana, that exist
only as tiny gametophytes, which reproduce only asexually. They never
form the larger sporophytes which are what we think of as the typical
fern plants.
http://www.ibiblio.org/unc-biology/herbarium/weakley/Vittar.html
http://www.goldsword.com/sfarmer/ATBI/gametophyte-gallery.html

There is a cycad species, Encephalartos woodii, in which only a single
male plant survived in the wild. It has been reproduced by offsets and
still survives in many botanic gardens. 
http://www.plantzafrica.com/plantefg/encephwoodii.htm

King's holly (Lomatia tasmania) exists in the wild as a single
specimen that reproduces only asexually because it is triploid. It is
thought to be as much as 43,000 years old.
http://www.ou.edu/cas/botany-micro/ben/ben149.html

Genetically seedless fruit, such as seedless grapes, cultivated banana
and navel oranges cannot set viable seed so have to be asexually
propagated.

David R. Hershey


"Tristan" <hamlet2b at videotron.ca> wrote in message news:<hkI39.2721$qu1.136901 at weber.videotron.net>...
> Hello,
> 
> I have been debating with a friend about whether or not any plants reproduce
> only asexually, or whether all plants have some mechanism of sexual
> reproduction.  Our research has unveiled many forms of asexual reproduction,
> but there is usually an implication that the same plants also reproduce
> sexually.  Are there any species anyone knows of that reproduce only
> asexually?
> 
> Thanks



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