132 



MANUAL OF BOTANY 



Verbena^ where the calyx and corolla have five parts in each 

 whorl, and the andrcEcium and gynoecium only four. 



In an isomerous flower the number of parts is indicated by 

 a Greek numeral prefixed to the termination -merous. Thus, 



Fig. 2-t 



Fie. 246. 



Fig. 245. Flower of Crassula nihins. c, c. Sepals, p, p. Petals, f, c, e. 

 Stamens, o, o. Carpels, at the base of each of which is seen a scale, a, «. 

 Fiff. 246. Flower of a Sedum. 



when there are two leaves in each whorl, as in Circeea {fig. 

 247), the flower is dimermis, and the symmetry is said to be 

 binary or two-membered. This arrangement is thus marked, 

 v/. "When there are three parts in a whorl, as in the Squill, 



Fir,. 247. 



Fig. 24S. 



Fig. 247. Diagram oftheflowerof Circeea. Fig, 248. Diagram of the flower 



of StaphyUa pinnata. 



Iris, and LUy, the flower is trimerous, and the symmetry is 

 ternary, trigonal, or triangular ; it is indicated thus, ^ . 

 "When there are four parts- in a whorl, as frequently in the Rue 

 (fig. 282), the flower is tetramerous, and the symmetry, which 

 is marked i/ , is guatemary or tetragonal. "When there are 

 five parts in a whorl, as in Crassula rubens {fig. 245), the 

 flower is said to be pentamerous, and the symmetry, which is 

 marked thus, ^ , quinary or: pentagonal. 



Of the above arrangements, the pentamerous is most common 



