Handbook of Nature-Study · Lesson CLXXVII · Topic 26: Ferns, horsetails and mosses
177. The field horsetail
Goal: Your child can describe the two very different stems of the horsetail and explain that the spore stalk makes spores and the green stalk does the work of leaves.
You'll need
- A few horsetail stalks with their roots, from a sandy roadside or bank
- A sheet of white paper
- 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 two parts, each with a leading thought: the pale fertile plant of early spring, with its spore "blossom," and the green, bushy sterile plant that comes up weeks later.
The lesson, step by step
When and where
This lesson comes in two visits. In April and May look on sandy or gravelly ground, railway banks and roadsides (stay well away from the tracks) for pale pinkish stalks topped with a cone. In September or October go back for the green, bottle-brush plants.
Dig up one or two with their underground stems, and wash hands afterward.
The leading thought
The horsetail is a plant that develops spores instead of seeds, and has green stems instead of leaves.
The spring stalk
Look at the pale stalk together and ask:
Where are these plants found? On what kind of soil?
In what respect does this plant differ from other plants in appearance? Can you find any green part to it?
Do you see any leaves on the stems? Do you see the black-pointed scales? In which direction do these scales point?
Shake out the spores
Take one of the plants which has the discs surrounded by green ridges. Shake it over a white paper. What comes from it? Where does it come from?
Look at the green dust through the lens. Which discs on the stalk shed their spores first?
The green stalk (autumn)
Read the second leading thought:
It lacks leaves, but its branches are green and do the work of making food for the plant.
Then ask:
Has this plant any leaves? How does it make and digest its food without leaves? What part of it is green?
Take off one little branch and study with the lens. How does it look? Pull it apart? Where does it break easily?
Children love pulling the joints apart and fitting them back together.
Look underground
What kind of root has the horsetail? Do you think this long running root is the true root or an underground stem? Where are the true roots?
Look for the small tubers along the rootstock. The book says they store food for next year's spore stalks.
Nature notebook
Draw the spring stalk and the autumn plant side by side, with the date you found each. Label the spore cone, the black scales, a joint (node) and the green branches.
Remind everyone: horsetails are not food. Wash hands after handling them.
Tip
Horsetail stems feel gritty because they hold tiny bits of silica. Pioneers scrubbed pots with them, which is why one kind is called "scouring rush."
Answers to the book's problems
The rings of black-tipped scales are tiny leaves; the green branches and stem make the food. The long running "root" is an underground stem (rootstock); the true roots grow from its joints.
Worked out for this site from the scan. If a number in your copy differs, trust the book.