The
Magnoliidae
Family Overview - The Nymphaeales
Nymphaeaceae - the Water Lily Family
Diversity: A family
of
5 genera and about 80 species of perennial, aquatic herbs.
Distribution:
Worldwide
(cosmopolitan). 4 genera in the Texas flora, each with 6 species.
Floral structure:
Significant features:
Classic archaic floral structure, many parted, solitary with poor
differentiation
between the calyx and corolla with gradation extending to the
androecium.
This combines, however, with specialization for a specific habitat - an
aquatic environment. All species are aquatic, perennial herbs
with
underwater rhizomes and long-petioled, peltate leaves. The Nymphaeales
is one of the few angiosperm Orders with all taxa adapted to a specific
habitat. Also, all taxa of lack vessel elements. It is
believed
that this is a derived condition (ancestors had vessel elements in the
xylem) related to the aquatic environment of these plants.
Monocots
also tend to lack vessel elements in the xylem. This, and other
linkages,
have suggested to Cronquist that "..the premonocotyledonous dicots
were
probably something like the Nymphaeales." Thus, of all dicot
Orders and Families considered here, this one carries a possible link
to
the monocots.
Nymphaea
- water lily flower at anthesis
Victoria
cruziana - flower with leaves - stem (rhizome) under water
Victoria cruziana
- leaf with scale (herbarium
botanist)
More information on the Nymphaeaceae
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