262 



Pontederiaceae. 



Because of the suggested close relationship of this family with 

 the order of Helobiales it is of interest to note that at least one 

 representative of Pontederiaceae, 



Heteranthera reniformis 



displays a striking resemblance in the general features of pollen 

 formation with the members of the order mentioned. Not only is 

 the successive biparlition the rule, as far as I have seen, without 

 exception, but also a tapetum is formed out of the peripheral parts 

 of the sporogenous tissue. 



Stetnonaceae. 



In this family I have been able to record the pollen development 

 for the two species 



Stemona moluccana Engl. and S. javanica Engl. Both species show 

 successiv biparlition. The spore mother cells are remarkably small, 

 augmenting but liitle in size during the divisions, and their walls 

 remain very thin. The general appearance of microsporogenesis here 

 agrees closely with e. g. Flagellaria. 



Liliaceae. 



The mode of pollen formation is now known for a comparatively 

 great number of species belonging to this family, and it has been 

 ascertained that both bipartion and quadripartition occur in mem- 

 bers systematically quite nearly related. In this connection it is 

 perhaps worth mentioning that an analogue variation in the deve- 

 lopment of the female gamophyte has been found. 



I have observed the successive bipartion in 



Sanseviera macrophylla Wallr. and 



Eustrephus latifolius R. Br. 

 A very illustrative exemple of quadripartition is 



Dianella spec. 



Here a complete series of stages made it possible to make a 

 detailed account of the formation of the partition walls in the 

 spindles after the second division of the mother cell. No traces of 

 a cell plate could be seen during the heterotypic division. 



