40 MONTANA AGRICULTURAL COLLEGE SCIENCE STUDIES. 



Ruppia occidentalis, Wats. Gravelly Range Lake, Lewis & 

 'Clark Co., Aug. 1902, Owen Byrnes, No. 39. 



ALISMACE^. 



Sagittaria arifolia tenuor, n. var. 



Scapes equaling the rather short peduncled leaves, which have 

 the median lobes narrow and acute and basal narrow and spreading. 

 Phyllodia not infrequent; otherwise like the type. This might be 

 mistaken for 6\ latifolia c of Smith, except for the short, erect beaks 

 to the akenes. 



Flathead river, July 20 and 23, 1900; Flathead lake, Aug. 1897, M. 

 J. Elrod; Three Forks, Aug. 24, 1903. 



Sagittaria latifolia, Willd. ; Rydberg, Flora, 19. It is still doubt- 

 ful if this species occurs in the state and no specimens appear yet 

 to have been collected within our limits, those so referred being the 

 next, which is difficult to separate from it except in mature fruit. 



Sagittaria paniculata, n. sp. 



Large, 2-6 dm. high, growing in shallow water, roots tuberous; 

 leaves thick, 10-18 cm. long, ovate with spreading basal lobes, equal- 

 ing the median in length, latter gradually narrowed to an acute 

 apex; petioles stout, exceeding the scapes: inflorescence verticillate- 

 paniculate, 3-4 lower whorls pistillate; bracts scarious, ovate-lance- 

 olate, 10-20 mm. long; peduncles 5-10 mm. long; flowers 18-22 mm. 

 in diameter, filaments equaling or shorter than the anthers : fruiting 

 heads 10-15 mm. in diameter: akene obovate-cuneate, 2.5-3 mm. long") 

 beak minute, erect or slightly retrorse. [PLATE VI.] 



.S\ arifolia, Nutt. differs from this in its smaller size (1-2 dm. 

 high), smaller, thin leaves (5-10 cm. long), abruptly rounded to an 

 obtuse apex with basal lobes shorter than the median, its slender 

 petioles shorter than the scapes, its racemose inflorescence with 

 shorter (5-10 mm.) bracts, its smaller (7-10 mm. diam.) fruiting 

 heads and smaller (2 mm.) akenes. 



In general habit it approaches more nearly 3\ latifolia^ Willd., but 

 differs from it in the shorter beak to the akene and short filaments, 

 which are similar to arifolia with which it intergrades. It is not a 

 hybrid between the two, for latifolia is not known in this region. 



Found throughout the plains region of the state. Box Elder Cr., 

 Valley Co., July 14, 1900; Three Forks, Aug. 24, 1903; Wibaux, 

 Aug. 15, 1903; Miles City, Aug. 16, 1903; Bozeman, Aug. 31, 1898. 



