158 THE AMERICAN BOTANIST 



Stiff spines on the jaws interlock and form a cage from which 

 only a very tiny insect can escape and which only the most 

 powerful, if any. can open. Then, very deliberately, taking 

 many hours, the jaws close tighter, forming at last a water 

 tight compartment which holds the victim and the juices 

 which destroy and devour it. 



If a leaf closes from being touched by a straw, or, on 

 anything which is not food, it will open again, taking 

 several hours to do so, but, a good meal is apt to prove fatal 

 to the leaf. Whether these insectivorous plants have any 

 economic importance as insect destroyers or not, owing to 

 the profusion of the plants the destruction is enormous. 



ELEMENTARY SPECIES OF RUDBECKIA 



By WiLivARD N. Clute. 



O EVERAL genera in the Compositae tend to vary con- 

 ^^ siderably in the color-patterns of their flowers. In this 

 connection there comes to mind the cultivated Coreopsis 

 with rays marked with brownish-red, the cone-flower {Lc- 

 pachys colmmiaris) which occasionally produces ray-flowers 

 with brownish markings, the red sunflower, introduced to 

 the trade some time ago, and last but by no means least, 

 Rudhcckia liirta whose flower-heads have outdone all other 

 Composites in the variety of their markings. 



As the plant grows in our fields and meadows, the rays 

 are a clear, deep yellow but it is not difficult to find plants 

 with a flush of red on the rays. From a single individual 

 of this kind, found in the wild, has sprung a race of pied 

 individuals which are sufficiently distinct in themselves to be 

 separated into several easily recognized strains. 



