BULLETIN 
OF THE 
TORREY BOTANICAL CLUB. 
Vol. XVIII.] New York, August 8, 1891. (No. 8. 
Notes on North American Haloragee. 
By THomas MOorRonac. 
The order Haloragee consists mostly of aquatic plants, and, 
as arranged by Bentham and Hooker, comprises nine genera, 
four of which occur in northern North America and one other in 
southern Mexico. These genera differ widely from each other in 
some important points, but so far as the structure of the ovules 
and embryos is concerned, form a very natural family. The 
Order was formerly classed by most botanists with the Onagracee, 
and in some botanical works many of the genera are still retained 
in that family, but they evidently differ radically from the mem- 
bers of that Order in nearly all the essential ordinal character- 
istics. Ceratophyllum was included among the Haloragee by 
Bentham in his Flora Australiensis, but probably by mistake, 
as the peculiar embryo, the four verticillate cotyledons and the 
exalbuminous ovules of Ceratophyllum absolutely forbid its intro- 
duction into this group of plants. Curiously enough, too, 
Bentham’s own ordinal description debars this genus from a place 
here. 
The only objection to the arrangement of Bentham and 
Hooker which is likely to be made is in regard to the position of 
Callitriche, which has commonly been regarded as unique and 
as constituting an Order by itself. Upon a careful examination, 
however, it cannot be doubted that in habit, in its four-carpelled 
fruit, its ovules and embryos, this genus bears a very close rela- 
_ tionship to Myriophyllum, while in the stamens and styles it 
strik ingly resembles —— especially those forms es af, 
