Sounds like the silversword alliance. Yes, there was a documentary on this.
This plant group is mentioned in General Botany books as an example of
adaptive radiation. Judy Kelly

From the University of Hawaii website --
http://www.botany.hawaii.edu/faculty...ilversword.htm
"Members of the tarweed subtribe (Madiinae) of the sunflower tribe
(Heliantheae) of the aster family (Asteraceae), the Hawaiian silversword
alliance consists of about 30 species in three genera (Argyroxiphium,
Dubautia, and Wilkesia). The species exhibit an extraordinary range of
anatomical, morphological, and ecological adaptations but are exceedingly
closely related as judged by data from biosystematics and molecular studies.
The evidence favors the conclusion that all of this diversity evolved from a
single ancestor that colonized Hawaii by way of long-distance dispersal from
North America. More information on adaptive radiation, hybridization, and
evolution of this group is linked here. For further information and photos
related to individual species, click on a genus below. "



"Gabriel" wrote in message
om...
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.