94 



Tamarix and Dionaea (Fig. 5) are examples of basal plac- 

 entation. In basal, as in parietal, placentation, there is little dif- 

 ference between buds and adult flowers. The placentation and the 

 tufted seed of Tamarix arc somewhat suggestive of Salix and 

 Populus, known to be very early dicotyledons. In Dionaea the 

 beginning" ovary is widely open. There are no ovules in the center 



Fie 5. Venus's Fly trap (Dionaea mitscipula) . Placentation from 

 young Bud to mature Flower. (10,201) 



of the young bud. resembling in tins respect Nymphaea. In other 

 words, there is a sterile area in the center, reminding us that the 

 flower is a determinate axis. In Cactaceae there is usually parietal 

 placentation with many ovules. Hut the genus 1'ereskia is an ex- 

 ception in having basal placentation, with only few ovules, much 

 like Dionaea. Hereskia is generally considered primitive among 



