THE LEAF 



193 



digests the meal. After a number of days, varying according 

 to the digestibility of the diet, the blades slowly unfold again 

 and are ready for another capture. 



The bladderwort, common in pools and still waters nearly 

 everywhere, has its petioles transformed into floats, while 





FIG. 264. Bladderwort, showing finely dissected submerged leaves 

 bearing bladders for capturing animalculae. 



the finely dissected, rootlike blades bear little bladders which, 

 when examined under the microscope, are found to contain 

 the decomposed remains of captured animalculse. 



Practical Questions 



1. Can you find any kind of leaf that is not preyed upon by something ? 

 If so, how do you account for its immunity ? 



2. Make a list of some of the most striking of the protected leaves of 

 your neighborhood. 



3. What is the nature of the protective organ in each case ? 



4. For protection against what does it seem to be specially adapted ? 



5. Are the plants in your list for the most part useful ones, or trouble- 

 some weeds ? 



