Taxonomy
of Flowering Plants - LECTURE
NOTES
Hugh
D. Wilson
The Caryophyllidae
Subclass Caryophyllidae is made up of only 3 orders,
14
families and about 11,000 species. The large, diverse Order Caryophyllales
includes about 90% of the species and also carries the relatively
distinct
set of features that mark the Subclass. These
include:
- anthocyanin
pigments
typical
of most angiosperms are lacking in most families of the
Caryophyllales
and replaced by a class of pigments, betalains,
that are found only in this Order (and some fungi)
- the Order is marked by a
suite of unusual
embryological features. The nutritive tissue, for instance, found
in the seeds of most Caryophyllales is not
endosperm.
It is derived from sporophytic (diploid) tissue and known as perisperm.
Also, the embryo tends to occupy a peripheral position in the
seed,
which often produces a characteristic 'beaked' (protrusion of the
radical)
asymmetry:
- mostly herbs but 'woody' elements of the subclass often show
anomalous
secondary growth
- the perianth tends to be
uniseriate
via apetaly
but often showy via petaloid sepals
- and the placentation
pattern
if often basal
or free central
thereby tending to place the ovules in a central position within the
ovary
- the archaic term 'Centrospermae'
denotes this tendency
Patterns of relationship, as defined by Cronquist,
within
the Subclass and its largest Order:
Redrawn from A. Cronquist
- Evolution
and
Classification of Flowering Plants, 2nd ed.
Our survey of the group will
include:
Caryophyllales
Phytolaccaceae
Cactaceae
Chenopodiaceae
(and
Amaranthaceae)
Caryophyllaceae
Nyctaginaceae
Polygonales
Polygonaceae
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301 homepage, Nomenclature,
or the
Hamamelidae