ELEMENTS OF STRUCTURAL BOTANY. 25 



32. Coming to the flower, olserve first that the parts 

 of the calyx are not entirely separate, as in the flowers 

 you have ah-eady examined. For about half their 

 length they are united together so as to form a cup. 

 The upper half of each sepal, however, is perfectly dis- 

 tinct, and foi*ms a tooth of the calyx ; and the fact that 

 there are five of these teeth shows us unmistakably that 

 the calyx is made up of five sepals. We therefore speak 

 of it as a (jamosepalous calyx, to indicate that the parts 

 of it are coherent. 



As the calyx does not fall away when the other parts 

 of the flower disappear, it is said to be persistent. Fig. 

 31, a, shows a persistent calyx. 



33. At the base of the calyx there are three minute 

 leaf-like teeth, looking almost like an outer calyx. A 

 cucle of bracts of this kind is called an iin-olncre. The 

 three bracts under the flower of the Hepatica also con- 

 stitute an involucre. As the bracts in the Mallow grow 

 on the calyx, some botanists speak of them as an ei>i- 

 cahj.v. 



The corolla consists of five petals, separate from each 

 other, but united with the stamens at their base. 



3-i. The stamens are numerous, and as their fila- 

 ments are united to form a tube they are said to be 

 inoiuuleljilious. This tube springs from the receptacle, and 

 the stamens are therefore hi/pot/i/nous. Fig. 32 will 

 help you to an understanding of the relation between 

 the petals and stamens. 



Having removed the petals, split the tube of the 

 stamens with the point of your needle. A little care 

 will then enable you to remove the stamens without in- 

 juring the pistil. The latter organ will then be found 

 to consist of a ring of coherent carpels, a rather stout 



