THE FLOWER OF THE HIGHER SEED-PLANTS 161 



Usually, as in Fig. 98, this is only a slight enlargement of 

 the flower-stalk, but in the rose (Fig. 102), the pond lily 

 (Fig. 115), the magnolia, the Calycanthus, and a good many 

 other familiar flowers it is large and con- 

 spicuous. 



180. The Perianth. — ■ The sepals, or divi- 

 sions of the calyx, are commonly green and 

 somewhat leaf-like. The petals in showy 

 flowers are of many colors, ranging all the 

 way from violet to red. Either whorl of the 

 perianth may be found to hstve assumed 

 some very peculiar form, to caiTy out the 

 purpose of the flower, as is briefly explained 

 in Chapter xvil. 



Among the lower families of seed-plants 

 with closed ovaries the parts of the perianth 

 are frequently all distinct, as shown in Fig. 98. Among the 

 higher families the members of the perianth are often borne 

 upon a tubular or cuplike outgrowth from the receptacle, 

 so that the sepals or petals or both appear to have grown 

 together more or less completely.^ 



When the calyx or the corolla is borne upon a tubular, 

 bowl-shaped, or other extension of the receptacle, there are 

 often divisions, teeth, or lobes at the rim of the tube show- 

 ing how many sepals or petals the flower possesses. 

 Special names are given to a large number of forms of the 



Fig. 102. 

 A Rose, Longi- 

 tudinal Sec- 

 tion. 



1 When the parts of the perianth are distinct, the calyx is said to be chorisep- 

 alous and the corolla choripetalous ; other terms are polysepalous and poly- 

 petalous. VFhen the receptacle forms a cuplike or tubular outgrowth, so that 

 the teeth or lobes of this alone are sepals or petals, the flower is said to be syn- 

 sepalous or sympetalous; other terms are gamosepalous or gamopetalous. 

 Choris means apart, poly means many, syn means together, gamos means 

 marriage. Botanists have until recently used such expressions as "sepals 

 united into a tube," etc., but these are incorrect. 



