544 Handbook of Nature-Study 



for a vacation study, and ask that their observations be kept in their note- 

 books. The study of the pods and seeds may be made in September or 

 October. When studying the milky juice, add a geography lesson on 

 rubber trees and the way. that rubber is made. 



Observations i. The plant. How does the milkweed look as it ap- 

 pears above ground in the spring? How are its leaves folded when it first 

 puts its head up? Cut off a fully expanded plant a few inches above the 

 ground. What flows out of the stem? Blot off the "milk" and study 

 the cross-section of the stem. What is at the center? How many layers 

 do you see around this center? Can you see from which the milkweed 

 juice comes? How does the juice feel as it dries on your fingers? How 

 does it look when dry? Place a few drops on a piece of paper and when 

 it is dry pull it off and see if it is elastic. Break the edge of the leaf. 

 Does the milky juice flow from it? Does it come from the veins? Do 

 you think that this is the sap of the milkweed? Cut a gash in the milk- 

 weed stem and see how the "milk" fills the wound. How does this help 

 the plant? Do cattle feed upon the milkweed when it grows in pastures? 

 If not, why? 



2. How are the leaves arranged on the stem? How do the upper and 

 under sides of the leaves differ ? Examine with a lens, and see what makes 

 the nap of the velvet. What gives the light color to the under side? 

 Sketch a leaf showing its shape and venation, noting especially the 

 direction of the veins as they approach the edge of the leaf. 



3. The flower. Where do the flower clusters come off the stems in 

 relation to the leaves? Does the stem of the flower cluster stand stiff or 

 droop? Take a good sized flower cluster and count the flowers in it. 

 What would happen if all these flowers should develop into pods? How 

 many flower clusters do you find. on one plant? Which of these clusters 

 open first? Last? 



4. Take off a single bud with its stem, or pedicel. Does the milky 

 juice come at the break? Is the bud stem stiff or drooping? What is its 

 color and how does it feel? What is the shape of the bud? How many 

 sepals has it? Look at the stem, sepals and bud with a lens and describe 

 their covering. Look for a flower just opening where the petals stand out 

 around it like a five-pointed star. What is their color? What happens 

 to the petals when the flower is fully expanded? Can you see the sepals 

 then? Look straight into the flower. Do you see the five nectar-horns? 

 Look at them with a lens and describe them. What do you suppose is the 

 use of the little curved tongue coming out of each ? Where does the tip 

 of the tongue rest? With a lens, look between two of the nectar horns; 

 can you see a little slit or pocket, with white protruding edges? Note just 

 above the pocket a black dot ; thrust a needle into this pocket near its 

 base and lift it toward the crown of the flower, touching the black dot. 

 What happens? 



5 . Describe the little branched object that came out when you touched 

 it with a needle. These are the pollen saddle-bags and each bag comes 

 from a pocket at one side of, and above the long pocket. Do these saddle- 

 bags cling to the needle? Look with a lens at some of the older flowers, 

 and see if you can find the pollen-bags protruding from the long pocket. 

 See if you can find how the long pocket is a passageway to the stigma. 

 To see how the little saddle-bags were transported, watch a bee gathering 

 nectar. Describe what happens. 



