THE FLOWER 



59 



There are many plants, however, in which stamens and pistils 

 are not found in the same flower. In such cases there are 

 two kinds of flowers, one staminate, the 

 other pistillate, both found on the same 

 plant (monoecious) or separate plants 

 of the same species (dioecious). 



129. The number of deviations from 

 the ideal flower just described are too 

 many to be enumerated, but it will be 

 necessary to indicate the most impor- 

 tant ones in order that homologies may 

 be recognized, 



130. The receptacle may be either 

 convex, flat, or concave. In the latter 

 case the edges of the receptacle may 

 rise so high around the gynoecium as 

 to entirely enclose it within the con- 



. Fig. 29.— Diagram of a 



cavity. (bee Fig. 27.) pistil with one ovule in the 



131. The calyx is very rarely want- Zr/yis^l^ti^.V^^l 



ing since its function is that of protec- 's attached by a stalk, the 

 -p „ , funiculus, and is provided 



tion. Its parts may all be separate with two protective layers, 

 sepals, but frequently there is a more ^^^ j^'' Vi!^ T^\ '"^ •^"" 



^ . ments, which develop into 



or less complete union of the edges of the seed coats. The cm- 



ii, 1 -ii 1.1 J r bryo is developed from the 



the sepals with each other so as to form egg nucleus (small circle) 

 a cup or tube (calyx gamosepalous). ^^^icli lies in the embryo 



r . sac (large oval). The cm- 



132. The corolla is often entirely bryo sac is embedded in a 



wanting. In other cases it is present, ™-:„°' %Z%^^, et 



but inconspicuous. Usually, however, bryo is nourished by the 



, , n • • • contents of the embryo sac 



when the corolla is present it is very and the nucellus. Reserve 



conspicuous because of the size and [°°^ contained in the em- 



•^ ^ bryo sac is called cndo- 



color of its parts. Like the calyx it sperm while that found in 

 1 1 r 1* ^« ^ ^ the nucellus is perisperm. 



may be made up of distinct parts, or 



the parts may be more or less united into a single structure 



(corolla gamopetalous). 



