5.3 Class Magnoliopsida – flowering plants - Cambridge University ...

epidermal glands but in different families the glands are adapted
to produce either mucilage (in Polygonaceae), excrete salt as in the
halophytes, or digestive enzymes in the insectivorous Droseraceae and
Nepenthaceae. In the latter, the gland-type is shared but the subsidiary
insect-trapping apparatus is quite diverse ranging from pitchers
(Nepenthes), sticky traps (Drosera, Drosophyllum) to spring traps
(Dionaea, Aldovandra).
Several families in the order have a peculiar flower development
that starts in a polymerous way but becomes organised into a pseudodiplostemonous
way. Stamens appear to be produced in pairs. In
the Caryophyllaceae and Plumbaginaceae stamens are antipetalous
and arise with the petal as a unit.
Some families in the Caryophyllalaes (Caryophyllaceae, Chenopodiaceae)
generally lack mycorrhizae perhaps because they tend to
occupy nutrient rich fresh soils. In contrast, the insectivores in the
Nepenthaceae, Droseraceae and Drosophyllaceae can inhabit nutrientpoor
soils.
santalales (sandlewoods)
All five families of the Santalales (Santalaceae ∼500 species, Olacaceae
∼200 species, Opiliaceae 28 species, Misodendraceae 8 species, and
the Loranthaceae ∼940 species) include tropical parasitic species. The
Loranthaceae are the most specialised parasites. The shrubby, liane
or twining habit is common throughout the order.
saxifragales (saxifrages, currants and stonecrops)
The Saxifragales is a very diverse order and includes: trees
(Hamamelidaceae ∼100 species of witch hazel and sweet gum, Cercidiphyllaceae
-- katsura, Altingiaceae), shrubs (Grossulariaceae ∼325
species of currants and gooseberies) and showy ornamentals like the
Paeoniaceae (∼34 species of peony), but the two largest families are
herbs, mainly rosette-forming Saxifragaceae (∼475 species of Astilbe
and saxifrage) or leafy succulents, the Crassulaceae (∼1280 species of
Sempervivum, Echeveria, Sedum and Kalanchoe). Many of these rosette
formers in the Crassulaceae, Saxifragaceae and some other small
families, are linked by a similar look to their flowers and a number
of characters such as a persistent scarious calyx and cellular
endosperm.
vitales (vines)
This order is of supreme importance to us as the source of wine from
the grape vine Vitis. Many other genera are twining vines with or
without tendrils (Rhoiocissus, Cissus). Cyphostemma is a caudiciform and
Leea a shrub and small tree.
berberidopsidales
This tiny order of two families, one with only one species Aextoxicon
from Chile and the other with only two genera Berberidopsis and
Streptothamnus from Chile and eastern Australia.
5.3 CLASS MAGNOLIOPSIDA – FLOWERING PLANTS 239
Figure 5.87. Aizoaceae:
Mesembryanthemum.
Figure 5.88. Grossulariaceea:
Ribes.
Figure 5.89. Paeoniaceae:
Paeonia.
Figure 5.90. Berberidopsidales:
Berberidopsis.