255] FLORA OF BOULDER, COLORADO 107 



344. P. Douglasii Greene. Douglas's knotweed. 

 Common in open, especially sandy places throughout, 5100- 



10000 ft. (Daniels, 958). 



Vermont to British Columbia ; New York to New Mex- 

 ico and California. 



344a. P. Douglasii consimile (Greene) Small [P. consimile 

 Greene]. Branched Douglas's knotweed. 



Gregory Canon, 6000-6300 ft. (Daniels, 546). Lower Boul- 

 der Canon (Rydberg). 



Range of the type? 



128. PERSICAPJA Adans. Smartweed. Lady's 



THUMB. 



345. P. emersa (Michx.) Cockerell. Nov. comb. [Polygonum 

 Muhlenbergii S. Wats; Polygonum emersum (Michx.) 

 Britton]. Muhlenberg's lady's thumb. 



Along ditches and in swales in the plains, 5100-6000 ft. (Dan- 

 iels). 



Maine to British Columbia ; Virginia to California and 

 Mexico. 



346. P. lapathifolia (L.) S. F. Gray [Polygonum lapathifo- 

 lium L.]. Dock-leaved lady's thumb. 



Swales and ditches in the plains, 5100-6000 ft. (Daniels, 

 506). 



Europe: Asia: North America. 



347. P. Persicaria (L.) Small. [Polygonum Persicaria L.]- 

 Common lady's thumb. 



Common in waste places, and along ditches and in swales, 

 5100-6000 ft. (Daniels, 517). 



Europe, thence to North America. 



348. P. punctata (Ell.) Small [Polygonum punctatum Ell.; 

 Polygonum acre H. B. K.]. Water smartweed. Dotted 

 water pepper. 



Margins of ponds, in swales and springy grounds, 5100-6000 

 ft. (Daniels, 798). 

 North America: Central America: South America. 



