CHAPTER XXXV. 



ARRANGEMENTS OF THE PARTS OF THE 

 FLOWER. 



This chapter is for reading and reference. 



363. Relations of the parts of the flower. — In some plants 

 the parts of the flower are distinct, and in others they are more 

 or less united. Definite terms are used to indicate these rela- 

 tions of the parts of the flower. In trillium and dentaria which 

 we have studied, all the sets, or whorls of parts, axe free; i. e., 

 no one floral set is adherent to another. The pistils make one 

 set, the stamens another, the petals another, and the sepals 

 another set. These sets are all free in their insertion on the 

 receptacle of the flower. The receptacle of the flower is that 

 portion of the stem where the flower parts are attached. 



Further the parts of the calyx, corolla, and andrcecium are 

 distinct. That is, the parts (sepals) of the calyx, for example, 

 are not united together by their edges. 



In the buttercup family, represented by the marsh marigold 

 (figures 221, 222) all parts of the flower are both free and dis- 

 tinct. 



364. Parts of the flower coherent. — But in both trillium and 

 dentaria the parts of the gyncecium are coherent, i. e. , the 

 carpels (three in trillium and two in dentaria) are united into a 

 single, compound pistil. 



So in any set when the parts of that set are partly or com- 

 pletely united they are said to be coherent. The stamens are 

 coherent by their anthers in the bell flower and in most of the 

 flowers of the composite family, as in the aster (see fig. 242), 

 sunflower, golden rod, etc. 



221 



