BY A. H. S. LUCAS. 42l 



one of the chief points relied on in the differentiation of species 

 of Elatine, the discrepancy in the numbers seems fatal to the 

 inclusion of our plants, with flowers almost constantly trimerous, 

 in E. americana, with flowers almost constantly dimerous. On 

 the other hand, there is much less reason for separating the Aus- 

 tralian form from the older species, E. triaiidra. 



I have lieen able to compare our plants with specimens, in the 

 Herbarium of the Botanic Gardens, of E. americana and E. 

 triandra, both from the United States. The facies of the Aus- 

 tralian form agrees well enough with either — as do the dimen- 

 sions of parts ^but the predominance of trimerism of parts 

 brinss it into much closer relation with E. t7-iandra. The differ- 

 ences appear to be too small to justify the creation of a new 

 species, and 1 propose, therefore, to include our Elatine in E. 

 triandra Schrank. 



