32 PRELIMINARY STUDIES. 



of the Spruce. Is the arrangement the same on all the 

 different kinds of Spruce you can find ? Would the 

 arrangement of the leaves help to distinguish the different 

 kinds of Spruce trees? 



Consulting Gray's " Manual of Botany," determine the 

 names of all the different kinds of Pine and Spruce trees 

 you can find. 



3. With a hand lens notice the rows of stomata run- 

 ning lengthwise of the leaves. What purpose do stomata 

 serve ? Tear off bits of the epidermis and examine the 

 stomata under the compound microscope. Draw them 

 as seen under both low and high powers. 



4. In May or early June find Pine trees bearing little 

 cones clustered about the base of the new growth at the 

 ends of the branches. These are the staminate or male 

 flowers. Continue to watch these flowers until they shed 

 their pollen. Observe in what profusion it is produced, 

 and how it is carried by the wind to long distances. 

 Why is it necessary that anemophilous flowers should 

 bear such an abundance of pollen ? Examine the stamens 

 of which the male flower is composed under a magnifier 

 and under the low power of the compound microscope. 

 Find the pollen sacs. Are they borne on the upper or 

 under side of the stamen ? How do they open ? Draw 

 a stamen, showing the pollen sacs and their dehiscence. 

 Examine some of the pollen grains under both low and 

 high powers. Draw one. 



5. Also in May or June find small pinkish cones near 

 the tips of the new growth at the ends of the branches. 

 Dissect one of these cones, noticing that it is made up 

 of very thin leaves and of thicker ones that bear naked 

 ovules. After the ovules have been fertilized, the leaves 

 composing the cone shut together and protect the fer- 

 tilized ovule while it is developing into the seed. 



Are the ovules in the Angiosperms naked? The word 



