The native waterlilies of Australia are not often found in cultivation,
largely because the whole group is more sensitive to the cold
than other tropical waterlilies. They belong to the Nymphaea
subgenus Anecphya. The members of the group look so similar that
they were all originally to be varieties of the type species
Nymphaea gigantea. Now, some botanists have started to
convert the varieties into a number of separate species. Nymphaea
immutabilis is separated from the type species N. gigantea
in that N. immutabilis flower petals usually do not fade
with age, while the type species petals generally do (a tough
call when you are faced with a white flower N. gigantea
or N. immutabilis). Other species formerly associated
with N. gigantea are now: N. macrosperma (flowers
smaller with fewer petals), N. atrans (petals darken to
maroon with maturity) and N. violacea (flowers without
a gap between the petals and stamens). As the Australian wetlands
are now being more thoroughly explored, more species will undoubtedly
be identified as time goes on.
The southernmost growing waterlily of the group is N. gigantea.
The location is in the streams surrounding Grafton, New South
Wales. This species extends northward to about Rockhampton, Queensland,
where we also find the southern limits of Nymphaea immutabilis.
Some merging between the two species is probable here.
Because of the heat requirements of the Anecphya group of
waterlilies, there are no native waterlilies in the more temperate
regions of Australia. There is, however, an introduced species,
Nymphaea capensis, which has taken over much of the unclaimed
waters of New South Wales. It is now making headway into the
areas formerly dominated by Nymphaea gigantea. In my last
trip to Australia (March 2006), I found that a creek in New SouthWales
that once contained only N. gigantea is now over half
populated with N. capensis.