POLTGONACEOUS GENBKA. 41 



in pools along the Platte, near Denver, August, 1881, L. F. 

 Ward, and at New Windsor, Weld Co., 31 July, 1894, Geo. E. 

 Osterhout. 



P. OTOPHTLLA. Evidently 3 or 3 feet high, suberect, slightly 

 flexuous ; very short-peduncled but ample leaves elliptic-lanceo- 

 late, abruptly acuminate, the narrow base subauriculately 

 rounded at the insertion of the petiole, the largest 5 or 6 inches 

 long, 2 in width, deep green above and scarcely roughened by 

 the faint though not very sparse minute strigose hairiness, be- 

 neath paler, inconspicuously strigose with longer softer hairs, 

 the midvein conspicuously clothed with very long comparatively 

 soft hairs that are rather ascending than appressed ; both the 

 'short thin ocrae and the striate internodes pubescent with very 

 straight and closely appressed hairs ; short peduncle similarly 

 appressed-pubescent and not glandular : bracts of the short 

 spike long-hairy both on the back and along the margin ; flowers 

 small for the plant. 



In swamps at Dallas, Texas, 11 Oct , 1900, J. Keverchon, 

 distributed by B. P. Bush, to U. S. Herb., under n. 2146. Spe- 

 cies particularly well marked by the long-soft hairiness of the 

 midvein of the leaf beneath. 



P. ABOKiGiKUM. Of the size of the last, rather more slender, 

 the geniculate stems more or less decumbent ; leaves narrower 

 exactly lanceolate, though with subcordate or subauriculate 

 base, rather obviously soft-strigose above, more densely and 

 silkily so beneath, where the midvein is clothed with very straight 

 and closely appressed long fine hairs : peduncles rather densely 

 appressed- villous without glands ; spike short, not surpassing 

 the leaves ; bracts villous-strigose : flowers small ; small chest- 

 nut-brown achenes orbicular and little compressed, almost 

 apheeroidal. 



Species of Oklahoma and the Indian Territory, collected by 

 Mr. Blankinship, 38 Aug., 1895. 



P. Langloisii. Evidently upright, several feet high, the 

 comparatively slender stems with notably short and thick nodes, 

 the striate internodes li to 3 inches long ; leaf blades elliptic- 



