368 THE STORY OF PLANT LIFE 



APOCARPEiE. 



In this series the flowers possess a coloured perianth 

 which is in two series, or green and in one series, or 

 imperfect or wanting. The ovary is superior, 

 apocarpous, or monocarpellary. The seeds do not 

 possess endosperm. The end of the embryo at 

 which the cotyledons are situated is narrower, hooked, 

 or coiled, and rarely straight. 



The AHsmacese or Water Plantain group and the 

 Naiadacese or Pondweed group are included in this 

 series. 



In the former the flowers are mainly hermaphrodite, 

 variable in the latter. 



In Alismacese the perianth is six-partite, four- 

 partite in Naiadacese, with an equal or greater 

 number of stamens. There are numerous carpels in 

 the Alismaceae, one to four in the Naiadaceae. In 

 the former the fruit consists of many achenes. In 

 neither groups do the seeds contain endosperm. 

 In both the radicle is very large. In each case the 

 plants are aquatic or marsh plants. In the Alismaceae 

 the flowers are large and coloured, in the Naiadaceae 

 they are small and green. These distinctions serve 

 well to separate the groups. 



86. The Water Plantain Group. 



Some fifty species arranged in ten genera are 

 included in the Order Alismacese. They are natives 



