Handbook of Nature-Study · Lesson CXCVII · Topic 28: Tree study
197. The cottonwood
Goal: Your child can describe cottonwood catkins and "cotton," and can show why its leaves twinkle in the wind.
You'll need
- Cottonwood or poplar twigs (February) or leaves (summer)
- A hand lens (magnifying glass)
- A nature notebook and a pencil (colored pencils if you have them)
What's in the book
The lesson has a leading thought, a method beginning with twigs forced in February, and eight observations on the bark and buds, the pollen and seed catkins (the "necklace"), the cotton, the size of the tree and the twinkling leaves.
The lesson, step by step
When and where
Bring in twigs in February to force in water. Watch the trees in spring, and look for "cotton" drifting in late spring or early summer. Cottonwoods grow along rivers and on the plains, and in many towns.
The leading thought
The cottonwood is a poplar. It grows rapidly and flourishes on the dry western plains where other trees fail to gain a foothold.
The catkins
Describe the catkin as it comes out. Has this catkin anthers and pollen, or will it produce seed?
Find a seed-bearing catkin. How long is it? Do you see why this tree is called the necklace poplar?
The cotton
How are the seeds floated on the air? Why do we call this tree "cottonwood?"
Catch some cotton and look with the lens for the tiny seed inside.
Why the leaves twinkle
Are the petioles round or flat? Are they flattened sidewise or up and down?
Blow against the leaves and see how they move? Do you understand, now, why they twinkle?
Nature notebook
Draw a leaf with its flat stalk, then draw the stalk again as if cut across. Glue or tape a bit of cotton with its seed to the page.
Answers to the book's problems
The leaf stalk is flattened sideways, crosswise to the broad, heavy leaf, so the leaf flips back and forth in the slightest breeze. The seeds float on tufts of white cotton. The book says the shiny leaves shed smoke and dust, which made it a good city tree.
Worked out for this site from the scan. If a number in your copy differs, trust the book.