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

232 ORDERING THE PATHS OF DIVERSITY
Figure 5.68. Lilium.
Figure 5.69. Veltheimia
bracteata (Eastern Cape Province,
South Africa).
liliales (lilies)
In contrast to the superficially similar Asparagales, the Liliales tend
to have nectaries at the base of the floral parts, spots on the petals
and stamens with anthers opening to the outside (Figure 5.68). Other
features like the cellular structure of the seed coat also link them.
Like the amaryllids they include many geophytes, producing bulbs
(Liliaceae, Melanthiaceae) or corms or rhizomes (Colchicaceae). Some
are shrubby or vines (Philesiaceae, Smilacaceae). They also include
chlorophyll-lacking mycotrophs in the Corsiaceae. There are four
main lineages: (1) Smilacaceae with Liliaceae; (2) Alstroemeriaceae
with Luzuriagaceae and Colchicaceae; (3) Campynemataceae; and
(4) Melanthiaceae.
asparagales (amaryllis, irises and orchids)
The Aparagales is the largest order of monocots and includes many
beautiful flowers (Figure 5.69). The Asparagales have a seed coat in
which cellular structure has become obliterated and there is a black
crust of phytomelan. Most Asparagales are rhizomatous herbs but a
few such as the Ruscaceae are shrubs (Ruscus) oreventrees(Dracaena).
Many of the most beautiful flowers are in a lineage of bulb-formers
that includes the Amaryllidaceae, Agapanthaceae and Alliaceae. Many
of these produce flowers in an umbel with a spathe at its base. The
Iridaceae (irises and crocus) are in a distinct lineage and are distinguished
by their divided style. Another interesting feature is that
they do not produce root-hairs and rely entirely on mycorrhizae for
garnering nutrients from the soil. The irises have a flower that provides
three distinct entry points for pollinators, and a petaloid stigma
overarching each of the three stamens. Another interesting lineage
is one including tussock formers and trees in the Xanthorhoeaceae
(grass-trees) and Asphodellaceae the aloes (Aloe) and red-hot pokers
(Kniphofia).
(a) (b) (c) (d)
Figure 5.70. (a) Watsonia, (b) Tulipa, (c) Xanthorhoea, (d) Moraea.