What Are Plants?

The study of plants is called botany. Early botany was important for the identification of medicinal plants.  The need to identify, describe, name, and classify plants, i.e., to catalog them, is basic to botany, because without this, one would not be able to communicate with others about specific kinds of plants. This aspect of botany is called taxonomy or systematics. The need to study and accurately describe the structure of plants led to the development of fields of morphology and anatomy.

 There are approximately 300,000 plant species known to science. 

Distinguishing characteristics of plants:

  • Cell walls built of cellulose, giving strength to the structure
  • Produce their own food through photosynthesis



 Visit the Illinois Plants Database for more information, photos and resources:

  • Iris

  • Fringed Gentian

  • Brome

  • Sand Dune WIllow

  • Yellow Coneflower

  • Prickly Pear Cactus in winter

  • Asiatic Iris

  • Asparagus

  • Beach Wormwood

  • Bear Berry

  • Bear Berry

  • Bindweed

  • Bird's Foot Trefoil

  • Bird's Foot Trefoil

  • Black-eyed Susan

  • Black-eyed Susan

  • Bottle Gentian

  • Butterfly Weed with Black-eyed Susan

  • Chicory

  • Compass Plant

  • Daisy

  • Daisy

  • Evening Primrose

  • Fleabane

  • Flowering Spurge

  • Flowering Spurge

  • Foxglove

  • Goldenglow

  • Goldenrod

  • Touch-me-not/Impatiens

  • Joe Pye Weed

  • Juniper

  • Marsh Vetch

  • Common Milkweed

  • Monkey Flower

  • New England Aster

  • Phlox

  • Pale Purple Coneflower

  • Pickerelweed

  • Pickerelweed

  • Prairie Coreopsis

  • Purple Coneflower

  • Sand Reed

  • Rose

  • Smartweed

  • Soapwort

  • Goldenrod

  • Spiderwort

  • Sundrops

  • Sunflower

  • Tansy

  • Trailing Juniper

  • Verbain

  • Joe Pye Weed

  • Prickly Pear Cactus in winter


Basic Plant Taxonomy

Charophytes are non-vascular aquatic plants.

  • algae






Embryophytes are the land based plants.

Non-vascular plants lack xylem and phloem to transport water and nutrients


  • mosses
  • liverworts
  • hornworts






Vascular Plants have a system made up of xylem and phloem for transporting water and minerals through the plant, allowing them to grow larger.

Spore Producing Plants

  • ferns
  • horsetails
  • club mosses





Seed Producing Plants

  • Angiosperms - Flowering plants
  • Gymnosperms - Non-flowering plants


Other botanical fields of study include:

  • cytology is the study of the structure and reproduction of plant cells;
  • physiology is the study of chemical and physical processes of plant life, such as photosynthesis, respiration, and differentiation;
  • ecology is the study of relationships between plants and their environment; and plant geography, the study of the distribution of plants.
  • paleobotany is the study of fossil plants.
  • algology or phycology is the study of algae.
  • bryology is the study of mosses and liverworts.
  • pteridology is the study of ferns.



Retired INHS botanist Dr. Ken Robertson also has a wealth of botanically related information on his home page.


Some past articles published in INHS Reports:

The Role of Insect Flower Herbivory in Native and Restored Prairies. Winter 2002

Effects of Exotic Plants on Bird Nesting Success. Autumn 2001

Biotic Inventory of Kyrgyz Grasslands. Autumn 2001

Land-cover Classification for Forests. Autumn 2001

Species Spotlight: Poison Ivy. Summer 2001

INHS Inventories Smoky Mountains Flora. Summer 2001

Species Spotlight: Bald Cypress. Fall 2000

Exotic Vegetation in Illinois Wetlands. Fall 2000

Environmentally Friendly Gardening. March-April 2000

Plant Stress--Its Relationship to Arthropod Pests in Urban Landscapes. March-April 2000

Species Spotlight: Tulip Tree. January-February 2000

Community-Level Parameters as Indicators of Restoration Success in Fire-Effects Studies. November-December 1999

How Prescribed Fire and Management Affects Plants and Animals in Central Illinois' Oak-Hickory Forests. November-December 1999

Fen Wetland Restoration in Northeastern Illinois. November-December 1999

Restoration of Bottomland Forests in the Cache River Watershed. November-December 1999

Prairie Restoration Research at the Savanna Army Depot. November-December 1999

Midewin National Tallgrass Prairie: History and Current Research. November-December 1999

Restoration Ecology and Research at the Illinois Natural History Survey. November-December 1999

The Role of Fire in Maintaining Plant Diversity in Oak Woodland Communities. May-June 1999

INHS Plant Collection. March-April 1999

The Naturalist's Apprentice: Dyeing With Plants. March-April 1999

Forest Regeneration and Understory Dynamics Following the 1993 Flood on the Illinois River. January-February 1999

Grassland Habitats in Illinois. July-August 1998

Species Spotlight: Bird's-eye Primrose. March-April 1998

Fire, Savanna Restoration, and Avian Populations in Midwestern Oak Forests. January-February 1998

White Grub Management Options in Turfgrass. January-February 1998

Species Spotlight: The American Lotus. July-August 1997

Species Spotlight: The Shooting Star. May-June 1996

Botany of the Savanna Army Depot. March-April 1997

Wetland Restoration at the Middle Fork River Forest Preserve. January-February 1996

Species Spotlight: Witch Hazel. January-February 1996

Plants of the Oakwood Bottoms. November-December 1995

Flooding Effects on Urban and Community Trees. July-August 1995

The Plants of Site M: a True Macrosite. May-June 1995

Species Spotlight: The Pitcher Plant. January-February 1995