134 ELEMENTS OF STRUCTURAL BOTANY. 



example. When a labiate corolla presents a wide opening 

 between the upper and lower lips, it is said to be ringent ; 

 if the opening is closed by an upward projection of the 

 lower lip, as in Toadflax (Fig. 181), it is said to be 

 personate, and the projection in this case is known as the 

 palate. A good many corollas, such as those of Toadflax, 

 Dicentra, Snapdragon, Columbine, and Violet, have 

 protuberances or spurs at the base. In Violet one petal 

 only is spurred ; in Columbine the whole five are so. 



Fig. 179. Fig. ISO. Fig. 181. 



210. ^Estivation. This is the term applied to the 

 mode in which the sepals and petals are folded in the 

 bud. In general, the members of a calyx or of a corolla 

 overlap in the bud, or they do not. If they stand edge 

 to edge, as in the calyx of Mallow, the aestivation is 

 valvate. If there is overlapping, and one or more of 

 the members have both edges covered, the aestivation is 

 imbricate; and if each member has one edge covered 

 and the other uncovered, as in the corolla of Mallow* 

 Evening Primrose, Phlox, &c., it is then said to be con- 

 volute. Gamopetalous corollas are frequently plaited in 

 the bud, and the plaits may be convolute, as in Morning 

 Glory. 



Fig. 179. Salver-shaped corolla of Phlox. 

 Fig. 180. Labiate corolla of Turtle-head. 

 Fig. 181. Personate corolla of Toadflax. 



