Lesson CXCVII

The Cottonwood

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. It grows well in the dusty city, its shining leaves shedding the smoke and dirt.

Method—Begin this study in spring before the cottonwoods bloom. Bring in twigs in February, give them water and warmth, and watch the development of the catkins. Afterwards watch the unfolding of the leaves and study the tree.

Observations—1. What is the color of the bark on the cottonwood? Is it ridged deeply? What is the color of the twigs? Are they round or angular, or both? Describe the winter buds and bud-scales. Can you tell which bud will produce leaves and which flowers?

2. Describe the catkin as it comes out. Has this catkin anthers and pollen, or will it produce seed? Do you think the seeds are produced on the same trees as the pollen?

3. Find a pollen-bearing catkin. Describe the stamens. Can you see anything but the anthers? On what are they set? What color are they? What color do they give to the tree when they are in blossom? What happens to the catkins after their pollen is shed?

4. Find a seed-bearing catkin. How long is it? Do you see why this tree is called the necklace poplar? Describe the pistils which make the beads on the necklace.

5. When do the seeds ripen? If you have been near the tree, how do you know when they are ripe? How long is the catkin with the ripened seeds? How many balls on the necklace now? What is the color? How many seeds come out of each little pod? How are the seeds floated on the air? Why do we call this tree “cottonwood?”

6. How large is the largest cottonwood that you know? Sketch it to show the shape of the tree. Are the main branches large? Do they droop at the tips?

7. How does the foliage of the cottonwood look? Does it twinkle with the wind? Examine the leaves upon a branch and see why they twinkle. Are the petioles round or flat? Are they flattened sidewise or up and down? Are they stiff or slender? Describe the leaves, giving their shape, veins, edges, color and texture above and below. Are the edges ruffled as well as toothed? Is the leaf heavy? If a breeze comes along how would it affect such a heavy, broad leaf on such a slender, thin petiole? Blow against the leaves and see how they move? Do you understand, now, why they twinkle? Can you see why the leaves shed smoke and dust, when used for shading city streets?

8. Why is the cottonwood used as a shade tree? Do you think it makes a beautiful shade tree? How long does it take it to grow? What kind of wood does it produce? For what is it used?

Supplementary reading—Trees in Prose and Poetry, pp. 139–149.