96 



Principles of Plant Culture. 



ist in determining species, and also to the plant breeder 

 who would practice cross-pollination (151, 440), hence 

 we need to consider them in detail. The cherry blos- 

 som, of which a vertical section appears in Fig. 45, will 

 serve as our first example. 



141. The Calyx (ca'-lyx). Beginning at the bottom, 

 the part marked C in the figure is called the calyx. This 

 is green in the normal cherry flower. In some plants, 

 as the flax, the calyx is composed of several distinct, 



c more or less leaf- 



c like parts, each of 

 which is called a 

 , ^ sepal (se'-pal) . In 

 the cherry blos- 

 som, the sepals are 

 united nearly to 

 the top. The calyx 

 is usually green, 

 but in the tulip and some other flowers it is of another 

 color. In the apple and pear, the calyx becomes a 

 part of the fruit, and its points are visible in the de- 

 pression opposite the stem. 



142. The Corolla (co-rol'-la). The more spreading 

 part of the cherry blossom, which is normally white 

 (Cor., Fig. 45) constitutes the corolla. In the cherry, 

 the corolla consists of five distinct parts, only three of 

 which appear in the figure, called petals (pet'-als) . In 

 many plants, as the pumpkin and morning glory, the 

 petals are united. In other plants they are united a 

 part of the way to the top. The corolla is usually of 

 some other color than green. 



Fig. 45. 

 calyx ; Cor. 



Section of cherry blossom. 

 coroUa ; S. stamens. 



