136 



DICOTYLEDONS 



Sepals (s) five, imbricate. Petals (/) five, separate. Stamens 

 5 + 5, with their filaments sHghtly combined at their bases. 

 4k The stamens {pa) forming the 



"" outer whorl are opposite the 



petals (obdiplostemonous) and 

 are shorter than those {sa) op- 

 posite the sepals ; anthers, in- 

 trorse. Nectaries \n) five lumps 

 opposite the sepals, and lying 

 \ between them and the five inner 

 stamens. Carpels five, syncar- 

 pous, superior. Ovary (pv) five- 

 lobed, five-chambered ; each 

 chamber contains two ovules 

 attached to the axile placenta. 

 Style single, but dividing above 

 _ into five branches with stig- 



Fig. 166.— Floral diagram of Herfc Robert. jjja,s (sg). It is important tO nOte 



that the ovary-chambers and five style-branches are opposite to 



the petals. Thus the five carpels 



are opposite to the petals instead 



of being opposite to the sepals : 



this is an additional peculiarity of 



many obdiplostemonous flowers. 



Fruit (fig. 167). — The main single 



part of the style elongates, and 



becomes a strong "beak." Only 



one ovule in each chamber forms 



a seed. When the fruit is ripe, 



as it dries, the five carpels separate, 



one by one or simultaneously, from 1 



below upwards in such a manner 



that the five seed - containing 



chambers (cocci) are carried up 



by elastically curling strips of the 



"beak," and are thrown off. The 



fruit is a peculiar schizocarp, 



because the carpels do not 



open whilst still attached to the 



mother - plant. In some of the 



British species of Geranium the 



Fig, 167. — Fruit of Herb Robert. 



