Seed Plants II: Angiosperms
Changing Concepts About Early Angiosperms
Classification of Flowering Plants
Basal Angiosperm
Monocots
Commelinoid Monocots
Eudicots
Rosid Clade
Asterid Clade
Basal Eudicots
100 years ago the Ranalean flower hypothesis was developed by C. E. Bessey
when a flower is generalized is has all parts
most botanists concluded that angiosperms are monophyletic
this includes double fertilization, flowers, and development plasticity
they believe they transition from gymnosperm to angiosperm occurred during the Jurassic period and Lower Cretaceous Periods
they can see this kind of things through fossils
the oldest wood was found in Japan 125million years old
Magnoliophyta is a large group
they are described as either monocots or eudicots; some are tricky to identify
monocots usually have parallel veins,vascular bundles, and do not have ordinary secondary growth and wood
their flowers are in multiples of threes
eudicots are more diverse
their flowers occur in sets of 5 or more
the early angiosperms diverge into several clades now called basal angiosperm
this group contains the living descendants of several groups the originated while the angiosperm were still young
the extant descendants of this group include Amborellales(Small Trees), Nymphaeales(water lilies), and Austrobaileyales
the water lilies live as rhizomatous aquatic herbs in temperate and tropical climates around the world.
these small trees are found in the forests of New Caledonia; dioecious with small flowers
all three have undergone massive change since their clades originated
Asparagales
Liliales
Dioscoreales
Alismatales
Poales
Zingiberales
Arecales
Caryophyllales
Santalales
very large and very diverse clade
contains many aquatic herbs and aquarium plants
found is swamps and marshes
they have no transpiration; air chambers make the plant buoyant
"petaloid" monocot; 11 families and 1,300 species
the petals often have spots or lines on them
only one family
their carpels fuse side by side being called septa; the open area secretes nectar
the flowers are large and colorful
important food crop called yams
Yams are starchy "tubers"; they have broad leaves with reticulate venation
These are different from other monocots because they have epicuticular wax, their waslls have unusual types of hemicellulose, and untra-violet compounds
the palms; 3500 species with their solitary trunk
scattered vascular bundles; leaves are near the apex
the leaves are simple that can be tor by wind into different patterns
grass family; 8000 species; they include wheat, barley, rye, corn, rice, and sugar cane
they are abundant in flat, open dry regions in the central area of all continents
grasses are wind pollinated; sepals and petals are not important
cattails grow in ponds and marshy areas;they produce fruits and flowers
closely related are the sedges and rushes; they live in marches with tiny flowers and small dry fruits
familiar house plants such as Maranta and canna lilies
they often have large showy flowers; adjacent sepals
distinctive feature includes three germination pores(tricolpate): their flower parts are arranged in whorls
this group includes cacti, iceplant, and Russian thistles
they produce water soluble pigments called betalains; the endosperm never fully grows so instead they produce perisperm
sieve tube plastids
most a parasitic and live with their host plant
the common mistletoe is apart of this group; have chlorophyll and are photosynthetic
they all share enough in common to be classified together
the two large clades are the Fabids and the Malvids; over 100 families; 14 large orders with 50,000 species
important characteristic is the pinnately compound leaves
the Fabales, Myrtales, Malpighiales,rosales, and sapindales contain 75% of the species
produces roses and apples
contains plants such as sunflowers, periwinkle, and petunias
they have sympetalous flowers, they always have just a few stamens, and the stamens alternate with petals
it does not contain betalains alkoloids, or ellagic
60,000 species