Rydberg: Studies on the Rocky Mountain ^iora 101 



SPARGANIACEAE 



Spargankim simplex L. has been reported again and again from 

 the Rocky Mountains, but all the specimens I have seen under that 

 name belong either to S. longipedunculatum (Morong) Rydberg 

 or to 5. angustifolium Michx. S. longipedunculatum resembles S. 

 simplex much in habit but is usually more slender, and the leaves 

 are not so triangular-keeled as in that species. The main 

 difference is, however, in the shorter style and stigma. 5. simplex 

 is very rare in the United States. I have seen specimens only 

 from the State of Washington. It is otherwise found in British 

 Columbia and along the St. Lawrence River in Ontario and Quebec. 



ZANNICHELLIACEAE 



Potamogeton perfoliatiis is not found in the Rocky Mountain 

 region. It is there represented by P. Richardsonianus. Notwith- 

 standing the fact that N. Taylor includes the latter in the former, 

 I am convinced that they are distinct. This opinion is based on 

 field studies. My contentions are also supported by M. L. 

 Fernald. 



I cannot find any specific distinctions between Ruppia curvi- 

 carpa A. Nels. and R. maritima L. The length of the pedicels is 

 merely a matter of age and other conditions; the typical R. 

 maritima has strongly oblique fruit, gibbous at the base as de- 

 scribed in R. curvicarpa; slender or stout, straight and curved 

 styles are found in the same individual even. Taylor, also, could 

 find no distinctive characters. 



ALISMACEAE 



Alisma Plantago-aquatica L. is not found in America. In this 

 European species the achenes have different beaks from those 

 found in the North American species. The common species of 

 the Rocky Mountain region should be known as ^. hrevipes Greene. 

 Alisma Geyeri Torr. is also found in the regions. (See my Flora 

 of Montana.) It has been collected later in Utah. 



Blankinship* described one new species and one new variety 

 of Sagittaria. S. paniculata Blank, is but a well developed S. 



* Loc. cit. 40. 



