Reproduction and Germination. 



4S 



seedling floats. ^\'hat would be its probable fate in a sluggish 

 stream ? 



Germinate seeds of skunk cabbage {Spathyeina), or any 

 convenient bog or land plant, and note the position of the 

 seedlings in water. This 

 will determine whether 

 the plant is adapted to 

 develop its seedlings in an 

 aquatic habitat or not. 



41. Sprouting of 



sweet potatoes Place 



several sweet potatoes 

 {Ipomea) or yams in moist 

 earth, and water freely. 

 Keep in a room slightly 

 warmer than an ordinary 

 living-room, and note the 

 development of buds which 

 form the characteristic 

 trailing stems of this plant. 

 Compare the position of 

 the stems when a few cen- 

 timeters in length, and the 

 positions of the tips when 

 a length of half a meter 

 has been attained. Note 

 the movements of the apical 

 portions of the stems. Mark 

 off a number of intervals 

 on the stems, and determine the rate and region of elonga- 

 tion. Are the earlier leaves similar in form and size to those 

 on older stems? 



Trail some of the stems across a box containing moist soil, 

 and note the formation of numerous adventitious roots. Cut 



Fig. 23. — Germination of Peltandra virgi- 

 ntca. A^ gelatinous mass, formed from 

 outer integument, serving as a flotation 

 organ. 



