FLOWERS 



109 



known as the receptacle shown in Fig. 92, B. This varies much 

 in shape in different kinds of flowers, being sometimes nearly 

 flat-topped, as in the lotus (Nelumbo) ; 

 usually convex, as in the buttercup, 

 raspberry, and strawberry; sometimes 

 very concave or even flask-shaped, as in 

 the sweet-scented shrub and the rose. 

 99. The perianth. 

 The calyx and co- 

 rolla taken together 

 are known as the 

 perianth. It is con- 

 venient to have a 

 name which includes 

 them both, as in many 

 flowers, such as those 

 of the Lily family, it 

 is difficult or impos- 

 sible to detect any 

 marked distinctions 

 between sepals and petals. In most flowers the sepals are 

 green or greenish and the petals of some other color, ranging 



FIG. 97. Flowers of common asparagus 



A, staminate flower, with perfect stamens (s) and 

 rudimentary pistil (rp) ; jB, pistil late flower, with fully 

 developed pistil (p) and rudimentary stamens (rs). 

 Such a flower is practically unisexual, but would 

 seem to have become so by descent, with modifica- 

 tion, from bisexual ancestors. After H. Miiller 



W 



FIG,, 98. Bilaterally symmetrical 

 corolla of sweet pea 



A, side view ; B, front view dissected ; 

 s, standard ; w, w, wings ; k, keel 



B 



from violet to red. There are, however, plenty of exceptions 

 to this rule. What are common instances of such exceptions ? 



