Angiosperms
Author: Ray Bowers

Description:
The name for the division comes from a similarity between the oldest fossil of flowering plants and the present day magnolias. The other word often used for this group of plants is angiosperms, which means vessel enclosed seeds, for example tomato seeds are enclosed in the tomato fruit. All angiosperms have flowers, but there is quiet a good deal of variation in shape, size, and parts. They all have vascular tissue in the form of veins in roots, stem, and leaves, although again there is quite a lot of variability in the shape and structure of these organs. The size of angiosperms can vary from 1.0mm (0.125in) to nearly as large as the conifers.

Geographic range:
The fossil record indicates that the flowering plants appeared about 160 million years ago during the late Jurassic Period. Presently they are found worldwide on land masses.

Habitat:
Angiosperms are found in all terrestrial habitats, and aquatic habitats with sufficient light and a stable substrate; they are not found in the open deep water or below the level of light penetration. Some are epiphytic, growing on other plants or even man-made surfaces. A few are parasitic, growing on and getting energy from other plants.

Some plants have developed a mutually beneficial relationship with other organisms. Some fungus fibers grow into and around plant roots, this increases the surface area that the roots have for absorbing water and minerals and the fungus gains nutrients from the plants. Nitrogen fixation is another example of a mutually beneficial relationship. Some plants have bacteria that can convert atmospheric nitrogen into a form that plants can use and the plants provide nutrients for the bacteria.

Reproduction and Development:
Sexual reproduction in flowering plants involves two types of reproductive cells. The female cell or ovule is enclosed within the tissue of the pistil. The male cells or pollen grains are not enclosed, but are at the end of the stamens, where they are carried away by a variety of agents. These agents could be the wind, water, or a variety of different types of organisms. The type of pollination depends on the type of plant. Fertilization occurs when a pollen tube carrying the sperm nuclei grows from the pollen grain at the top of the pistil to the ovule. Flowers vary in the shape, structure, size, and the presence of the parts in the illustration. Most plants have both male and female flowering parts and are considered dioecious plants, while others have only male or female flowering parts and are called monoecious plants.

Some plants can reproduce asexually, this means that the new plant would be genetically the same or a clone of its parent plant. In budding a new plant grows from a part of a parent plant. Another form of asexual reproduction occurs when a piece of a plant falls off, and starts to grow a new plant where it drops or is carried to another location where it starts to grow.

• Since most plants produce chemical energy during the process of photosynthesis, they play an essential role in most ecological systems as the primary source of energy or food. The vast majority of plant material that people eat comes from flowering plants, as well as the plant material that people feed to their domesticated animals. Plants also produce fibers, such as cotton, flax, and hemp that are used in a variety of different ways. Latex used to make rubber is from the sap of rubber trees.
  
• Medicines such as quinine and morphine are produced from some flowering plants. Alcoholic drinks are produced from the fermentation of fruits and grains. Chemicals, such as heroin, cocaine, or nicotine, from other plants can cause medical problems.
  
• A variety of flowering plant parts are used as dyes, such as the leaves of indigo. Flowering trees provide lumber used in construction as well as fine furniture.

Taxonomy:

Kingdom: Plantae
Division: Magnoliophyta, Flowering Plants
Class: Magnoliospsida, Dicots
Class: Liliopsida, Monocots

References:
Borror, Donald J. and Richard E. White. 1970. A Field Guide to the Insects of America North of Mexico. Boston : Houghton Mifflin Co.

Borror, Donald J., Charles A. Triplehorn, and Norman F. Johnson. 1989. An Introduction to the Study of Insects. Philadelphia: W. B. Saunders Co.

Bland, Roger G and H. E. Jaques.1978. How to Know Insects. Dubuque , Iowa : Wm. C. Brown Co.

Larson, Peggy and Lane Larson. 1977. The Deserts of the Southwest. San Francisco : Sierra Club Books.

MacMahon. James A.1985. Deserts. New York : Alfred A Knopf, Inc.

Werner, Floyd and Carl Olson. 1994. Insects of the Southwest. Fisher Books, LLC.

White, Richard E.. 1983. A Field Guide to the Beetles of North America . Boston : Houghton Mifflin Co.