Plant Identification (GMHDRNC)

Summary:

This program introduces taxonomy and how to use dichotomous keys. Participants will learn about branching, leaf arrangement, variation and how to use a sample key to identify plants. Collections can be made before class if weather prevents participants from going outside.

Grade Level:

K - 12

Recommended Setting:

Indoor and outdoor classroom

Outdoor Activity:

No

Location:

Governor Mike Huckabee Delta Rivers Nature Center, Pine Bluff

Contact:

Education Program Coordinator, 870-534-0011

Duration:

1 hour - 1.5 hours

Suggested Number of Participants:

10 - 20

Objectives:

  • Learn about native Arkansas plants and plant biology
  • Learn how to key out a plant with a dichotomous key.

Key Terms*:

Alternate leaf pattern

Bipinnately compound

Compound leaf

Dichotomous

Lobed leaves

Margin

Pinnately compound leaf

Serrated leaf

Simple leaf

Venation

*See glossary for definations

Materials:

“A Key to Common Trees of Arkansas”

Leaf diagrams

Plant/leaf samples

Background:

Plants are arguably the most important organisms on Earth. They are the base of the food chain, ultimately providing every organism with energy and nutrients. But also they provide the oxygen organisms need to live. Plant conservation is imperative, and exploitation of plants for materials can destroy entire ecosystems.

Procedure:

  1. Introduce plant biology (including photosynthesis) and plants’ role in the food chain. Ask the participants to name the parts of a plant and their functions. Cover parts from bottom to top.
    • The roots anchor the plant into the ground and stabilize it as well as absorb water and nutrients. The stem is the rigid structure that transports the water and nutrients from the roots to the leaves. It also stabilizes the plant. Whether a flower, fruit or nut, the center is where the plant reproduces. Pollen is mixed, and seeds fall to form new plants.
    • Photosynthesis in the leaves converts sunlight, carbon dioxide and water into glucose (an energy source) and oxygen. Besides converting harmful carbon dioxide into the oxygen living creatures need to survive, the glucose stored in plants is the base of the food chain. Herbivorous animals eat this glucose, gaining a percentage of the plant’s energy with smaller percentages passed up through the food chain.
  2. Discuss the types of leaves on trees, providing illustrations. Discuss leaf vocabulary such as venation, serrated and lobed.
  3. Distribute copies of “A Key to Common Trees of Arkansas” and show them how to key out a plant.
  4. Weather permitting, walk the discovery loop at DRNC with participants collecting leaves of their own. Once returned, have them key out the plants they have collected. Participants should key out as many of the leaves they’ve collected as possible and, optionally, a prize could be awarded to the one who correctly identifies the most leaves.

Review:

  • What is photosynthesis? How does it affect us?
  • What is a compound leaf? Name a plant that has this arrangement.
  • What does dichotomous mean?

Glossary:

Alternate leaf pattern – in a leaf, placed at different heights on the axis, on each side in succession, or at definite angular distances from one another

 

Bipinnately compound – having leaflets or primary divisions arranged on each side of a common stalk which are then arranged on each side of a larger stalk, as in a mimosa tree

 

Compound leaf – leaf that is divided into two or more distinct leaflets

 

Dichotomous – two divisions that contradict each other

 

Lobed leaf – leaves divided into segments with spaces between that do not reach the center

 

Margin (dendrology) – the edge of the leaf

 

Pinnately compound leaf – leaflets arranged along the mid-vein such as with the hickory and winged sumac

 

Serrated leaf – leaf with a bent, saw-like pattern along the edge

 

Simple leaf – leaf having one blade; or a lobed leaf in which the separate parts do not reach down to the midrib

 

Venation – arrangement of a vein system, as in an insect's wing or a leaf blade; some leaves have smaller veins branching out from larger ones in a pinnate or palmate pattern, while others have similar-sized veins running parallel along the length of the plant, connected by much smaller cross veins