In article ,
(Gabriel) wrote:
A few years ago, I have seen a documentary film about a plant in
Hawaii, I could not remember it's name, but it looked like a weed that
most people would not bother about it. This plant has quickly spread
to locations at various altitudes with climatic differences, and
therefore each plant has evolved into a different variation that
superficially looked very different from the original plant. I also
recall that the diverged species could be crossbred, because there was
not enough time to make genetic divergence, but I did not see how the
hybrid species would look like.

Maybe the data I'm providing is not enough to give a hint to the
species I'm inquiring about, but I can give you an example from the
world of cacti, with which I'm much more familiar: Most cacti can be
grafted on other types of cacti, because they are closely related,
although they look quite different: The ribbed structure of ferocacti,
the radiating shape of Mamillarias, the star-shaped Ariocarpus, and
the columnar Quiabentia which still carries leaves. If we
crosspolinate two different cacti and obtain viable seeds, how would
the hybrid look like ? Is there an example of such a plant I would
find i the market ?

This reminded me of the tale we heard at University years ago about
the Russian attempt to create a useful vegetable combination by
crossing a cabbage with a raddish. Unfortunately, it ended up with
cabbage roots and raddish leaves. :-)

Nevertheless, _Raphanobrassica_ exists as a fertile species following
doubling of the chromosome set.

Here's some detail on it's origin stolen from
http://www.biologie.uni-hamburg.de/b-online/e12/12c.htm

quoting
In 1928, G. D. KARPETSCHENKO (Institute of Applied Botany, Detskoje
Selo near St. Petersburg) produced a new species: Raphanobrassica (2n
= 36) by crossing Raphanus sativus (2n = 18; radish) and Brassica
oleraceae (2n = 18; cabbage). It seemed at first as if the hybrid was
sterile but after numerous experiments, a fertile specimen could be
found. Fertility was preceded by the doubling of the chromosomal set.
Accordingly, we have the following combinations: 9+9= 18 (sterile) and
18 x 2 = 36 (fertile).
/quoting

The above URL will take you to a page titled "The Formation of New
Species" which gives several such examples (and has a link to a neat
computer generated analysis of the lines of descent of 63 species of
_Nicotiana_ FWIW).





Cheers, Phred.

--
LID