130 



ELEMENTS OF STRUCTURAL BOTANY. 



which follows G show the carpels to be united, and the 

 placing of the figure above the short line indicates that 

 the ovary is superior ; if inferior, the figure would be 

 written below the line. Fig. 174 shows 



the plan of a Grass-flower. Here parts 

 which are suppressed, and the position 

 of which can in general be easily 

 inferred from that of those which are 

 present, are represented by dots. The 



Fig. 174. 



formula would be : K , C 2 , A 3+0 , 



199. The gynoecium is very frequently made up of 

 fewer members (carpels) than the other whorls, and in 

 all such cases the position of the carpels is more or less 

 irregular. 



200. Fig. 175 gives the plan of Shepherd's Purse. 

 This shows the four sepals to be in two whorls of two 

 sepals each ; the four petals, however, are arranged 

 alternately with the four sepals, as if 



the latter were all in one whorl ; the 



position of the stamens indicates that 



the two posterior ones, as well as the 



two anterior ones, occupy the place of 



single stamens, and have, therefore, 



probably arisen from the early division 



of single stamens into pairs. The Fi =- 175> 



formula would be : K 2+2 , C 4 , A 2+2 a, G(^); the expression 



2 2 indicating the reduplication of the inner stamens. 



201. If there is no clear distinction between the calyx 

 and corolla, the letter P (for perianth) may be used to 

 include both ; and, finally, if the members of any whorl 



Fig. 174. Diagram of a Grass-flower. (Prantl.) 



Fig. 175. Diagram of flower of Shepherd's Purse. (Prantl.) 



