PINGUICULA. 165 



The letters a and b (Fig. 14) represent the plant 

 P. pumila. This species is less in size than the two 

 previously mentioned, and has very small roots, barely 

 large enough to hold the plant in place. It blooms all 

 through the winter and early spring, constantly send- 

 ing up its pretty, one-flowered scapes, surmounted by a 

 white or purple blossom, until they reach the number 

 of fifteen or twenty. The flower scapes are from three 

 to six inches in height, brittle and delicate ; and yet the 

 roots are so small, even when the plants grow in damp 

 soil, that it is almost impossible to cull one of the flow- 

 ers without bringing up the whole plant ; and in the 

 more exposed dry places, when a plant had several flow- 

 er stalks, I have often found it tipped over, apparently 

 blown over by the wind. 



I observed the plants closely where they grew, and 

 found a great many minute dipterous flies on the leaves, 

 held there by the viscid exudation ; but I coidd only 

 know that they were of real use to the plant by re- 

 peated experiment and close observation, so I carefully 

 removed a number of fine plants to my study. 



Under the microscope the plant presents a beautiful 

 and complicated appearance. Along the midrib and 

 veins of the leaf are spiral threads closely coiled. One 

 of these spiral threads is represented by d as seen 

 through the microscope partly uncoiled. On breaking 

 the leaf and pulling it carefully apart the coils are set 

 free, and stand out from the broken edge of the leaf. 



The leaves are quite sensitive ; when the plants are 



