Plants that are sterile polyploids can only reproduce asexually.
Tristan <hamlet2b at videotron.ca> wrote in message
news:UY%39.3751$qu1.227864 at weber.videotron.net...
> This isn't the question. Asexual reproduction is acknowledged as being
> important for many plants, (especially artificially) but the question is
> whether most or all species are also to reproduce sexually to allow for
> survival in the face of environmental change and challenge.
>>> "Cereoid+1+" <cereoid at prodigy.net> wrote in message
> news:mb%39.416$H07.40213708 at newssvr16.news.prodigy.com...> > Absolutely untrue.
> > You never heard of multiplication by division?
> > Most plants in the horticultural trade are propagated entirely by
> > means.
> > David Hershey <dh321 at excite.com> wrote in message
> > news:7039c6ef.0208061750.52c787fc at posting.google.com...> > > 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
> > > > sexually. Are there any species anyone knows of that reproduce only
> > > > asexually?
> > > >
> > > > Thanks