Polygonum 



POLYGONACEAE 



411 



50 



Map 834 



Polygonum monspeliense Thiebaud 



50 



Map 836 



Polygonum aviculare L. 



knotweeds are more thoroughly studied it will be found throughout the 

 state. 



Nat. of Eu. ; becoming naturalized. 



4. Polygonum buxiforme Small. Map 835. This species is very local 

 but I believe when the knotweeds are studied more intensively it will be 

 found throughout the state. 



Ont. to B. C, southw. to Va. and Tex. 



5. Polygonum aviculare L. Knotweed. Map 836. An annoying weed 

 in gardens, truck gardens, lawns, pastures, and cultivated fields. It is found, 

 also, along logging roads in woodland, in fallow fields, and along roadsides. 



Found throughout N. A. and also in Eurasia. 



6. Polygonum neglectum Besser. {Polygonum aviculare var. angust- 

 issimum Meisn.) Map 837. Local. No doubt a more intensive study of 

 the knotweeds will greatly extend its range. In sandy to very sandy soil 

 in pastures, clearings, on black oak ridges, and along roadsides. Rydberg 

 gives its habitat as waste places and says it is more common than 

 Polygonum aviculare. 



Nat. of Eu. 



7. Polygonum tenue Michx. Map 838. This species prefers a slightly 

 acid soil and is generally found in exposed places without ground cover 

 and where there are very few or no other plants. In the lake area it is 

 generally found on the crests, slopes, and bases of black and white oak 

 ridges. South of the lake area it is generally found on sandstone bluffs, 

 on exposed crests of chestnut oak ridges, and in sandy places similar to 

 those in the northern part of the state. 



Maine to Man., southw. to S. C, Ga., and Tex. 



8. Polygonum natans A. Eaton f. genuinum Stanford. (Stanford. The 

 amphibious group of Polygonum, subgenus Persicaria. Rhodora 27 : 156- 

 166. 1925.) Map 839. All of our reports for Persicaria amphibia (L.) 



