I. Plants with an enclosed seed

A. Flowering plants today dominate the world’s vegetation

1. greatest biomass of most habitats is flowering plants

B. The defining angiosperm feature is enclosure of ovules within an ovary

C. In this text, Magnoliophyta is accepted as the name of flowering plant division

II. Mysterious origin of flowering plants

A. Flowering plants appear suddenly in the geologic record without a clear fossil history showing some transition from other plant groups

1. Upland theory

2. Bond’s seeding hypothesis

III. Novel Features of the Angiosperm Life Cycle

A. Angiosperms and Gymnosperms both produce seeds but differ in several life cycle features that adapt flowering plants to life on land and conserve food reserves

1. flowering plants show greater reduction in gametophyte size and complexity

2. location of the ovule becomes hidden

3. fertilization involves 2 steps with double-fertilization rather than one

4. seed dispersal is improved by its enclosure within a fruit

IV. Division Magnoliophyta

A. object of classification is to divide flowering plants into groups that show historic evolutionary linkages - classification should be phylogenetic

1. typically, Magnoliophyta is divided into to classes - Magnolipsida (dicots) and Liliopsida (monocots)

B. Phylogenetic Relationships are based on vegetative and reproductive traits

1. Bessey system found much favor in 20th century, still widely used

2. Besseys criteria

3. Takhtajan, Cronquist, Thorne and Dahlgren expanded Besseys criteria; Takhtajan uses criteria to divide the Magnoliopsida into seven subclasses, and Liliopsida into 3 subclasses

4. Subclass Magnolidae is the basis for both groups

5. new techniques are being used - analysis of protein structure, comparison of DNA sequencing, model building based on complex cladistics statistics

C. Magnolidae is the most primitive subclass

1. subclass contains tropical and warm-temperate trees with simple leaves, pinnate venation, large flowers with many stamens and pistils, and relatively simple wood anatomy; eg. Magnolia

2. other members of this subclass and close relative the Ranunculidae include: nutmeg, cinnamon, sassafras, avocado, bay laurel, black pepper, water lily, pitcher plant, opium poppy, buttercup family 

a. flowers of plants in these subclasses have regular symmetry, many separate parts and a superior ovary; typically beetle pollinated

D. The Alismatedae and Arecidae are primitive monocots

1. Liliopsida diverged early from Magnoliidae

2. Most primitive liliopsida are in the flowering rush family and the water plantain family, both in subclass Alismatedae

3. the Arecidae is a more advanced subclass, Arecaceae is the largest family in this subclass

4. palms are among the most important tropical families, coconut palm yields edible endosperm from huge seeds, oil pressed from dried coconut meat and cordage from stringy outer crust

5. Other notable members include duckweeds, taro plant, Philodendron, Anthurium and calla lily

E. The Liliidae arae the most advance monocots

1. one line includes orchids, lilies and bromeliads

2. the other grasses and sedges

F. Hamamelidae and Rosidae are Primitive Dicots

1. Hamamelidae are small subclass of temperate zone woody plnats, including important hardwoods of eastern forests

2. Rosidae is the most diverse subclass of dicots; among the families are bean, eucalyptus, rose and carrot

G. The Caryopyllidae, Dilleniidae and Asteridae are advanced dicots

1. largest families in subclass Caryophyllidae includes ice plants, cacti, and beets

2. The Dilleniidae subclass has many families but only a few are large - heather, mulberry, mustard, elm

3. The Asteridae, the most advanced dicot subclass - includes tomatoes, mints and sunflowers

a. Advanced traits include irregular flower symmetry, inferior ovary, small flowers and herbaceous habit

b. the largest of all flowering plant families is the sunflower family, the Asteraceae

V. Plant geography - describes the distribution of plant taxa

A. World’s flora is not uniform

B. Vegetation of a particular type of climate often looks similar wherever that climate recurs around the world, even if plants at each location are unrelated taxonomically

C. Environmental conditions, genetic potential and isolation growing in a place combine to create unique and bizarre vegetation found nowhere else in world

VI. Botanical Gardens