128 COMPOUND ORGANS OP PLANTS. 



Fig. 34. Fig. 35. 



The monopetalous corolla, has corresponding terms applied to 

 its modifications and to the degrees of cohesion amongst its petals. 



When the calyx falls as soon as the corolla expands it is 

 termed caducous, as in Sanguinaria Canadensis, which is at 

 first enclosed in a calyx of two leaves, which fall off as soon as 

 the flower is fully blown. The calyx is deciduous when it 

 drops off with the corolla, but in many cases, the calyx 

 remains after the corolla and other floral whorls have faded 

 and fallen, as a protecting envelope to the fruit, as in the 

 mallow, (Fig. 35.) In this case it is said to be persistent (per 

 through, and sisto to remain.) 



Sometimes the calyx and fruit cohere together, so that the 

 calyx appears to arise from the summit of the fruit, as in the 

 rose ; such a calyx is called a superior calyx ; if, on the con- 

 trary, the calyx and fruit do not cohere together, the calyx is 

 said to be inferior, as in the strawberry. In some plants 

 the calyx is suppressed altogether, or it may be present and 

 reduced to a mere rim or border, as in the Umbelliferse ; or to 

 a pappus, as in Compositae. 



A great many plants, however, have only one floral envelope 

 exterior to the stamens and pistils, as for example, the hyacinth 

 and the lily. The early botanists differed amongst themselves 

 as to the term by which this single floral envelope ought to be 

 distinguished from the others. Tournefort and Linnaeus called 

 it the calyx when it was green and bore the general character 



