DURATION 61 



Duration. — The duration of the perigone, especially of the calyx, 

 is frequently of considerable importance from the standpoint of phar- 

 macognosy, although in general not so. When a part falls away at, 

 or very shortly after, expansion it is Caducous. When lasting about 

 a day, and then either falling or i)erishing upon the flower, as in the 

 poppy, it is Fugacious. When lasting longer than a day, but falling 

 soon after fertilization, it is Deciduous. When remaining and retaining 

 more or less of its normal appearance for some time after fertilization, 

 it is Persistent. When so remaining, but in a withered condition, it is 

 Marcescent. These definitions assume that fertilization takes place 

 normally. If this be artificially prevented or deferred, the freshness of 

 a corolla is often very greatly })rol()nged. (See Fertilization.) Impor- 

 tant facts relating to the Accrescent calyx of the fruit will be i^resented 

 when the latter is discussed. 



Some very interesting facts concerning characteristic movements 

 of the corolla, its sleeping and awakening and other habits, should be 

 sought in general works on botany. 



