220 
IOWA ACADEMY OF SCIENCES. 
POLYGON ACE^E. 
Rumex L. 
215. R. altissimus Wood. Peach-leaved Dock. Com- 
mon in low ground. 
216. R . britdnnica L. Great Water-Dock. Frequent; 
borders of ponds, and along streams. 
217. B. crispus L. Curled Dock. An European species, 
introduced into cultivated fields. 
218. R. persicarioides L. (non R. maritimus L.) Com- 
mon in marshes. 
Polygonum L. 
219. P. amphibium L. Ponds and sloughs; frequent, the 
large leaves floating in the water. 
220. P. hartwrightii A. Gray. Very common in bogs, 
but rarely seen in flower or fruit. 
221. P. emersum (Michx.) Britton. (P. muhlenbergii 
Watson.) Very common in sloughs and low 
ground. 
221. P. incarnatum Ell. Common, especially in culti- 
vated ground, or near dwellings. 
222. P. pennsylvanicum L. Everywhere common. 
223. P. punctatum Ell. (P. acre H. B. K. non Lam.) 
Water Smart-weed. Common in low, w T et 
ground. 
224. P. aviculare L. Knot-grass, Door- weed. Every- 
where around dwellings. 
225. P. erectum L. Rather rare near dwellings. [Neither 
this nor the preceding species is probably native 
to our county, though indigenous to North 
America. 
226. P. ramosissimum. Michx. Common. 
227. P. convolvulus L» Black Bind-weed. A trouble- 
some European species, everywhere common in 
cultivated fields. 
228. P. scandens L. Climbing False Buckwheat. Com- 
mon in woods, where it climbs high over bushes. 
