FLOWEKS 



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 



B 



FIG. 97. Flowers of common asparagus 



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

 rudimentary pistil (rp) ; ^.pistillate 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 



FIG. 98. Bilaterally symmetrical 

 corolla of sweet pea 



A, side view ; B, front view dissected 

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



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

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



