No. 14.] FLOWERING PLANTS AND FERNS. 161 



rivers and ponds throughout. July — Aug. Perhaps in part 

 naturalized from Europe. 



Polygonum amphibium L. (growing on land or in water 



equally well). 

 Water Persicaria. 



Rare or local. Ponds and lakes: Preston (Graves), East 

 Haven (D. C. Eaton, Eames), Milford (Harger), Southing- 

 ton (Andrews, Bissell), Norfolk (J. H. Barbour), Ridgefield 

 and Kent (Eames), SaHsbury (Mrs. C. S. Phelps & Bissell). 

 Aug. — Sept. 



The var. terrestre Leers (terrestial) occurs rarely on 

 borders of ponds. 



The var. Hartwrightii (Gray) Bissell, Polygonum Hart- 

 zvrightii Gray, is rare or local on borders of ponds : Preston 

 and Griswold (Graves), Southington (Andrews & Bissell), 

 Norfolk (J. H. Barbour), Salisbury (Bissell). 



This species is remarkably variable according to the con- 

 ditions under which it grows. Intergrading forms connect 

 the typical form with the varieties and apparently with the 

 following species also. 



Polygonum Muhlenbergii (Meisn.) Wats. 

 Polygonum emersum Britton. 



Banks and shallow water about marshes, ponds and 

 streams. Frequent along the Connecticut River ; rare or local 

 elsewhere. Aug. — Sept. 



Polygonum pennsylvanicum L. 



Common or Pink Persicaria. Pink Knotweed. 



Frequent. Aloist rich soil in open situations. July — Oct. 

 Often a troublesome weed. 



Polygonum Careyi Olney. 



Rare, Moist or wet sandy soil about ponds and in open 

 swamps: Ellington (F, M, Pease), East Hartford (Weath- 

 erby), East Windsor, Windsor and Simsbury (Bissell), South- 

 ington (Andrews, Bissell), Waterbury (Andrews), Oxford 

 and Beacon Falls (Harger), Milford and Stratford (Eames). 

 July — Sept. 



