RYDBERG: STUDIES ON THE Rocky MounTAIN FLORA 101 
SPARGANIACEAE 
Sparganium 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 S. angustifolium Michx. SS. 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. SS. 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 perfoliatus 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 A. brevipes 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 Segtiaria, S. paniculata Blank. is but a well developed S. 
* Loc. cit. 40. 
