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 couccptacles, should be 

 seen opening exteriorly. In our common bladder-wrack, 

 Fucus vesiciilostis, these cavities will be found to contain 

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



