220 IOWA ACADEMY OF SCIENCES. 



• POLVGONACE^E. 

 RUMEX Tj. 



215. U. (iliiss'ninis Wood. Peacb-leavcd Dock. CJom- 



mon ill low ground. 



216. //. britdunica L. Great Water-Dock. Fre([ueiit; 



borders of ponds, and along streams. 



217. /i*. crispus L. Curled Dock. An European species, 



introduced into cultivated fields. 



218. /?. jicrsicarioides L. (non Ji. luarifinins L.) Com- 



mon in marshes. 

 Polygonum L. 



219. P. aiujiJilhiHnt L. Ponds and sloughs; frequent, the 



large leaves floating in the water. 



220. P. hartivrigldii A. Gray. Very common in bogs, 



but rarely seen in flower or fruit. 



221. P. emersiim (Michx.) Britton. {P. miihlenhergii 



Watson.) Very common in sloughs and low 

 ground. 

 221. P. incarnatum Ell. Common, especially in culti- 

 vated ground, or near dw^ellings. 

 P. peuusjjlranic}i}ii L. Everywhere common. ' 

 pioKidtum Ell. {P. acre H. 13. K. non Lam.) 

 Water Smart-weed. Common in low, wet 

 ground. 



ariciihu'c L. Knot-grass, Door-weed. Every- 

 where around dwellings. 



erect Kit! L. Rather rare near dwellings. Neither 

 this nor the preceding species is probably native 

 to our county, though indigenous to North 

 America. 



226. P.rmnosisslmum Mi(;hx. Common. 



227. P. conrnlvulns L. Black Bind-weed. A trouble- 

 some European species, everywhere common in 

 cultivated fields. 



228. P. scanthfts L. Climbing False Buckwheat. Com-- 

 mon in woods, where it climbs high over bushes. 



