266 Introduction to Botany. 



individuals are composed ? Leave some of the plants out 

 of the water for a time, and note what occurs to them. 



155. Spread out a few of the individuals in a drop of 

 water under a coverglass and examine with a medium 

 power of the microscope. Do the parts of which the 

 individuals are composed differ from each other in any 

 essential way ? Note the character of the walls and of the 

 contents. Is a nucleus to be seen ? What is the form 

 of the chloroplasts ? . Treat a preparation with chloral 

 hydrate-iodine, and note whether starch is demonstrated. 

 Does the nucleus become more prominent for a time while 

 the protoplasm is dissolving ? 



156. Examine some of the green, filamentous, felty 

 growth which abounds on moist shady banks. Is it ever 

 found in sunny situations ? Examine some of the fila- 

 ments, and try to determine how they are held together to 

 form the felty mass. Are they anchored to the earth, or 

 do they simply grow over its surface ? 



157. Mount some of the filaments in a drop of water 

 under a coverglass. Are they composed of cells, or does 

 each filament appear to be one large cell? Locate the 

 chloroplasts. Can more than one nucleus be found ? 



158. If living near the seacoast, observe the bladder- 

 wrack. How is it fastened to its substratum ? Is there 

 any special device to' keep the free parts buoyed up in the 

 water? Examine the enlarged ends and press them be- 

 tween thumb and finger while observing them with a lens. 

 Make thin sections through the swollen pitted ends, mount 

 in a drop of water under a coverglass, and examine with a 

 medium power. Small cavities, or conceptacles, should be 

 seen opening exteriorly. In our common bladder-wrack, 

 Fucus vesictilosus, these cavities will be found to contain 

 either the eggs or the sperms, this species being dioecious. 



