106 



THE FLOWER 



196. One-celled, with free central placenta. — The free central 

 placenta of the Pink (compare Fig. 140) may have come about by the 

 dissepiments having been suppressed in growth. 

 Indeed, traces of the original partitions are often to 

 be detected. On the other 

 hand, it is equally supposable 



138. 



Placentation 

 of Parnas- 

 sia. 



139. Placentation 

 of Drosera 

 filiformis. 



140. 



Pistil of Spergularia rubra, 

 one of the Pink family, with 

 free central'placentation. 



that in the Primrose (Fig. 160) the free central placenta has been 

 derived from parietal placentation by the united carpels bearing ovules 

 only at the base. Now, however, the placenta arises directly from the 

 end of the floral axis, not from the carpels. 



197. To the great majority of flowers with which one meets, one 

 or another of the above types wall apply. These types exhibit most 



clearly the structural principles of the 

 pistil. Occasionally, some different 

 mode of disposing the ovules or of 

 separating the ovary into chambers 

 will be discovered. 



198. Pistils of the Gymno- 

 sperms. — These are so distinct 

 and the group of plants wliich 

 produce tliem is so important 

 that they need a separate de- 

 scription. 



199. The fertile flowers of the 

 Pine ^ and other trees of the 

 same group appear in early spring 

 as small richly colored cones 

 (Fig. 141). The scales are soft, 

 and though not very thin are 



141. 



The flower of a Gynino- 

 sperm. At the right a 

 single carpellary scale 

 bearing two ovules. 



1 What is here designated a single female flower is also spoken of as 

 an inflorescence. 



