Lesson CLXIII

The Petunia

Leading thought—The petunias have an interesting history being native to South America. Their flowers are fitted by form and mechanism to entice the hummingbird moths as visitors, and to use them for carrying pollen.

Method—The petunias are such determined bloomers that they give us flowers up to the time of killing frosts, and they are therefore good material for nature lessons. Each pupil should have a flower in hand to observe during the lesson, and should also have access to a petunia bed for observations on the habits of the plant.

Observations—1. What colors do you find in the petunia flowers? If striped or otherwise marked, what are the colors? Are the markings symmetrical and regular?

2. Sketch or describe a flower, looking into it. What is the shape of the corolla-lobes? How many lobes are there? How are they veined? What peculiar markings are at the throat of the flower?

3. What are the color and position of the stigma? How are the stamens arranged? How many anthers do you see? What is the color of the anthers? Of the pollen?

4. Sketch or describe the flower from the side. What is the shape of the corolla-tube? Is it smooth or fuzzy? How is it marked? What are the number and shape of the sepals, or lobes, of the calyx?

5. Study a freshly opened flower, and describe the position and appearance of the anthers and stigma. Do they remain in these relative positions after the flower is old?

6. Cut open a flower, slitting it along the upper side. Describe the stamens and how they are attached. Is the pistil attached in the same manner? Where is the nectar? Thrust a slender pencil or a toothpick into the tube of a fresh flower. Does this spread the anthers apart and move them around? When it is withdrawn, is there pollen on it? Can you see in your open flower the mechanism by which the pollen is dusted on the object thrust into the flower?

7. What insects have tongues sufficiently long to reach the nectar-well at the bottom of the petunia flower? At what time do these insects fly? At what time of day do most of the petunia flowers open? Visit the petunia beds in the twilight, and note whether there are any insects visiting them. What insects do you find visiting these flowers during the day?

8. Sketch or describe the leaves of the petunia. How do the leaves feel? Look at a leaf with a lens and note the fringe of hair along its edges. Describe the veining of the leaf.

9. Describe the petunia stems. Are they stout or slender? How do they feel? With what are they covered? Where do the flower stems come off the main stalk?

10. Describe or sketch a flower-bud just ready to open. How are the tips of the lobes folded? How long does the flower remain in bloom? What is the first sign of its fading?

11. Describe the seed-capsule. Where does it open? Are the seeds many or few, large or small? What is their color when ripe? When examined with a lens, have they any pits or markings?