Seed Plants II: Angiosperms (Classification of flowering Plants (…
Seed Plants II: Angiosperms
it contains many aquatic herbs such as sagittaria.
plants tend to be thin and delicate, having very little sclerenchyma and almost no xylem.
plants are highly modified often having large leaves and considerable amount of fibers and thick cuticle on the leaf epidermis.
representative families of Alismatales
it is defined as the petaloid monocots with large colorful flowers.
they are smaller clades with approximately 11 families and 1300 species
most important feature is they have spot or lines on the petals and of rather ordinary nectaries formed at the base of the tepals.
it has ornamental plants
examples are: lilium, tulipa, calochortus etc.
this is a large clade
most form nectaries in a usual way but their carpels fuse side by side. the fused sides is called the septa.
examples are hyacinth, onion, chives, orchids etc
representative families of asparagales
small order with only one family'
it has familiar and important fppd crop like yam
they have petiolate, broad leaves with reticulate venation
it has about 3500 species which are easily recognizable by their solitary trunk.
they have scattered vascular bundles like that of most monocots
all species have simple leaves that are fully expanded y have either pinnate pattern or palmate one
egs: palm tree, coconut tree etc.
this order contains grass family poaceae as well as cattalis, bromeliads and sedges.
it has 8000 species
they include grass as well as wheat, barley, oats, corn, sugarcane etc. bamboo also comes under this group
representative families of poales
it contains some of the most familiar house plants like marantha, canathea, gingers, banana etc.
they have large showy flowers
its largest family zingiberaceae has around 1000 species
they produce a group of water soluble pigments called the betalains
their ancestral group may have lacked petals in their flowers.
endosperm develops a little and fails to continue growing
phloem plastids contains deposits of fibrous protein located as a ring just interior to the plastid membrane
highly modified plants most of which are parasitic
some are hemiparasitic while some are holoparasitic
this clade has plants which are diverse in many ways but they still have some common characters that put them under the same family
it has several orders and two large groups
the large clades of rosids are: fabids and malvids. they together have more than 100 families.
rose family is an important family of this clade
it is the most derived large clade of eudicots which contains plants such as sunflower, periwinkle,petunia and morning glory
it may have originated around 60 million years ago
they have sympetalous flower( their flowers are fused together)
they always have few number of stames( no more than the number of petals in that flower.)
the stames alternate with the petals
many asteroids have iridoid compounds
many asteroids are important medicinally
Changing concepts about early angiosperms
the early angiosperm used to be large bush or small tree while the present angiosperm are large trees, herbs, bulbs, vines etc
early angiosperm used to have evergreen leaf retention while the present angiosperm are deciduous or leafless
no vessels present in the early angiosperm while vessels are present in the present angiosperm(derived).
there used to be complete flowers in the early angiosperm while the present angiosperm have incomplete or imperfect flowers.
early angiosperm have radial symmetry while the present angiosperm have bilateral symmetry
Classification of flowering Plants
Nymphaeales (water lilies)
they contain the living descendants of several groups
that originated while angiosperms were still a young clade
their ancestors became reproductively isolated from the other early flowering plants before distinctive angiosperm traits had originated
they had nothing in common either with gymnosperms or seed ferns