POLYGONACEAE 79 
Outer calyx lobes winged and decurrent in fruit, achenes 4-5 mm. 
long. 24, P. scandens. 
Stems with recurved prickles. 25. P. sagittatum. 
1. Polygonum amphibium L. 
Polygonum coccinea Muhl. 
In water or sometimes in muddy places. Peru; Richardson County; 
Swan Lake. 
2. Polygonum hartwrightii A. Gray. 
In wet places and in shallow ‘water; perhaps only a form of Polygonum 
amphibium. Cherry County; Thedford; Valentine; Whitman. 
3. Polygonum emersum (Michx.) Britton. 
Polygonum muhlenberghii (Meisnr.) Wats. 
In wet places and in shallow water. Cherry County; Emerson; Ken- 
nedy; Richardson County; Whitman. 
4. Polygonum incarnatum Bll. 
In wet soil, not common. Kennedy; Lincoln; Long Pine; Nemaha; 
Red Cloud; Weeping Water. 
5. Polygonum lapathifolium L. 
A common weed in the eastern part of the state, less common in the 
western part. Dawes County; Mullen; Paddock; Red Cloud; River- 
ton; Talmage; Whitman. 
6. Polygonum pennsylvanicum L. 
Polygonum omissum Greene, | 
Common as a troublesome weed throughout the state. Boelus; Frank- 
lin; Indianola; Kearney; Lincoln; Mullen; Paddock; Red Cloud. 
7. Polygonum fersicaria L. 
Common in the eastern part of the state. Bassett; Callaway; Lincoln; 
Paddock; Valentine; Weeping Water. 
8. Polygonum persicarioides H. B. K. 
Over most of the state but not common. Newark; Thedford. 
9. Polygonum hydropiperoides Michx. 
In wet soil, not very common. Ainsworth; Atkinson; Callaway. 
10. Polygonum hydropiper L, 
In the eastern part of the state. Callaway; Franklin; Grand Rapids; 
Lincoln; Weeping Water; Nemaha. 
11. Polygonum punctatum Ell, 
Common in the eastern half of the state. Banner County; Grand 
Island; Hooker County; Indianola; Lincoln; Wahoo. 
12. Polygonum punctatum var. leptostachyum (Meisn.) Small. 
Thomas County; Hooker County; Grant County. 
13. Polygonum virginianum L. 
Common in the southeastern part of the state. Endicott; Lincoln; 
Nebraska City; Richardson County; Nemaha. 
14. Polygonum aviculare L, 
A common weed all over the state. Callaway; Ft. Robinson; Grand 
Island; Kearney; Lincoln; Mullen; Pine Ridge; Talmage; Thedford. 
15. Polygonum buxiforme Small. 
Common all over the state. Alliance; Cheyenne County; Hooker 
County; Mullen. 
16. Polygonum erectum Roth. 
Common in the eastern part of the state. Ewing; Ft. Robinson; Lin- 
coln; Talmage. 
