Handbook of Nature-Study · Lesson CXXXI · Topic 20: Summer wildflowers, climbers and water plants
131. The milkweed
Goal: Your child studies milkweed leaves, flowers and pods and explains how its pollen is carried in tiny “saddle-bags” on insects' feet.
You'll need
- Nature notebook, pencil and colored pencils
- A hand lens (magnifying glass)
- Garden gloves
- A small stick or old paintbrush
- A paper plate
What's in the book
A Teacher's Story with a photograph of milkweed seed-balloons and the lesson: Leading thought, a Method that spreads the study from spring to fall, and seven long questions.
The lesson, step by step
When and where
Common milkweed grows in fields and roadsides. Comstock suggests looking at the young shoots in April or May, the flowers in summer (about June and July), and the pods and seeds in September or October.
Safety: the milky juice is poisonous and stings the eyes. Wear gloves, keep hands away from the face, and wash hands afterward.
The leading thought
The milkweed when wounded secretes a milky juice which is of a rubberlike composition; it flows out of the wounded plant and soon hardens, thus protecting the wound from germs.
The seeds are carried by balloons, and they can float on water as well.
The milk
Comstock has children let the juice dry on their fingers. Do it more safely: with gloves on, break one leaf tip and dab a drop onto the paper plate with a stick. Check it in 10 minutes. Is it sticky? Stretchy when dry?
Comstock also suggests a geography talk on rubber trees and how rubber is made.
Leaves
How are the leaves arranged on the stem? How do the upper and under sides of the leaves differ?
The flowers
Take a good sized flower cluster and count the flowers in it. What would happen if all these flowers should develop into pods?
Look straight into the flower. Do you see the five nectar-horns?
Can you detect the strong odor of the flowers?
Use the lens on a flower still on the plant.
Watch the insects
Since the flowers bend over, how must the bee hold on to the flower while she gathers nectar from the horns?
Can you find on milkweed flowers any bees or other insects that have been entangled in these little traps and have thus perished?
Comstock suggests catching a bee to look at its feet. Don't; watch from a little distance instead. Look under the leaves too: striped monarch caterpillars eat only milkweed. Look, and leave them on the plant.
Nature notebook
Draw a flower cluster and one flower close up, showing the five little horns. In the fall, add a drawing of an open pod with its silky seeds.
Afterwards
In September or October, open a ripe pod outdoors, pull out a seed and let it go. Watch how far it floats. Count roughly how many seeds one pod holds.
Tip
If you grow milkweed for monarch butterflies, plant a kind that is native to your area.
Answers to the book's problems
The leaves are opposite. The pollen is in paired waxy sacs joined in a V; a visiting insect's foot slips into a slit and pulls out a pair, then leaves them in the slit of the next flower. Most flowers never become pods.
Worked out for this site from the scan. If a number in your copy differs, trust the book.