IO6 UNIVERSITY OF MISSOURI STUDIES [254 



127. POLYGONTIM L. KNOTWEED. 



336. P. erectum L. ERECT KNOTWEED. 



Along the railroad in Boulder Canon, 5500 ft. (Daniels, 580). 

 MAINE to ALBERTA ; GEORGIA to ARKANSAS and COLORADO. 



337. P. buxiforme Small. BOX-LIKE KNOTWEED. 



Bear Canon, and all waste places, 5100-10000 ft. (Daniels, 

 698). 



ONTARIO to WASHINGTON ; VIRGINIA to TEXAS and NEVADA. 



338. P. aviculare L. DOORWEED. 



Common about houses, along railroads, and in all waste 

 places, 5100-8000 ft. (Daniels, 582). 

 ASIA: EUROPE: NORTH AMERICA. 



339. P. ramosissimum Michx. BUSHY KNOTWEED. 

 Common along railroads and roads, and in low weedy 



grounds, 5100-10000 ft. (Daniels, 519). 



MINNESOTA to WASHINGTON ; ILLINOIS to NEW MEXICO and 

 NEVADA; MAINE to NEW JERSEY along the coast. 



340. P. Sawatchense Small. SAGUACHE KNOTWEED. 



High mesas at foot of the Flat-irons, 5700-6000 ft. (Dan- 

 iels, 178). 



SOUTH DAKOTA to WASHINGTON ; COLORADO to ARIZONA and 

 CALIFORNIA. 



341. P. confertiflorum Nuttall [P. Watsonii Small]. WAT- 

 SON'S KNOTWEED. 



About the quarries at foot of the Flat-irons, 5700-6000 ft. 

 (Daniels, 660). 

 MONTANA to WASHINGTON ; COLORADO to CALIFORNIA. 



342. P. unifolium. Small. ONE-LEAVED KNOTWEED. 

 Aspen bogs at Glacier Lake, 9000 ft (Daniels, 672). 

 MONTANA to COLORADO. 



343. P. Engelmannii Greene [P. tenue micros permum 

 Engelm.]. ENGELMANN'S KNOTWEED. 



Sandy stream-flats, especially common along the railroad in 

 Boulder Canon, 5100-10000 ft. (Daniels, 568). 

 MONTANA and COLORADO to BRITISH COLUMBIA. 



