PROPAGATION OF PLANTS. 209 



equally well ? Why ? What condition is present in one 

 pot that is not in tlie other? 



4. Geotropism. 



Experiment 22. — {a) Plant in moist sand or sawdust 

 a number of squash seeds and grains of corn in various 

 positions — some with either side down, some with eitlier 

 edge down, and some with either end down. 



[1)) Label each group as to position in planting. 



(r) After two or three days, examine to see if any of 

 the seeds have sprouted. 



{d) If so, note carefully the direction of radicle and 

 of plumule. J Draw. 



{e) Label according to position, and name all parts. 



(/) Now plant again, with the position of the seed 

 reversed. Repeat daily {d), [e), and (/) for several days. 



i^g) Does the position of the seed when planted have 

 anv effect upon the development of the embryo ? Ex- 

 plain. How do the results of your daily observations 

 compare with reference to the direction of growth of 

 radicle and plumule?* 



Experiment 23. — Stevens' " Introduction to Botany " 

 gives the following experiment in connection with geot- 

 ropism: "Remove the glass front and the hands from a 

 cheap alarm-clock. Provide a soft pine block about an 

 inch square, whittle one end to a taper, and drill a small 

 hole into it, so that it will slip through the opening of 

 the dial face and tightly over the hour-hand spindle. 

 Fasten a Petri dish to the outer face of the pine block 

 by a melted mixture of one-third beeswax and two- 

 thirds rosin, taking care to center the dish with the 

 hour-hand spindle. Pack moist pine sawdust into the 

 dish level with tlie surface, and press soaked grains of 

 corn into the sawdust, not very tightly, broad face down, 

 but do not cover them with sawdust. Put on the cover 



For parts of seed and seedling, see any good Botany. 



