126 FLOWER OF THE HIGHER SEED PLANTS 



152. The perianth. In dicotyledonous plants the sepals, or 

 divisions 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 have assumed some very peculiar form, to 

 carry out the purpose of the flower, as is briefly explained in 

 Chapter XXXIL 



Among the lower families of angiosperms the parts of the 

 perianth are frequently all distinct, as shown in Figs. 122 and 



134. Among the higher families 

 the members of the perianth are 

 often borne upon a tubular or cup- 

 like outgrowth from the recep- 

 tacle (Fig. 136, B), so that the 

 sepals or petals, or both, appear 

 to have grown togethef more or 

 less completely. 1 



When the calyx or the corolla 



is borne upon a tubular, bowl- 

 FIG. 128. Flower of Hydrophyllum -, j ,-, -0,1 



shaped, or other extension of the 



cal, lobe of calyx; cor, lobe of co- , ., ,. . 



roiia; st, stamens; P , pistil, receptacle, there are often dm- 

 Modified. After Lindiey sions, teeth, or lobes at the rim 



of the tube (Figs. 128, 144, Appendix) showing how many 

 sepals or petals the flower possesses. Special names are given 

 to a large number of forms of the sympetalous corolla, and 

 these are of much use in accurate descriptions of seed plants. 

 A few of these are illustrated in Chapter xxxn and in the 

 Appendix. 



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

 sepalous and the corolla choripetalous ; other terms are polysepalous and 

 polypetalous. When the receptacle forms a cup-like or tubular outgrowth 

 so that the teeth or lobes of this alone are sepals or petals, the flower is said 

 to be synsepalous or sympetalous ; other terms are gamosepalous orgamopeta- 

 lous. 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. 



