IOWA ACADEMY OF SCIENCE 
51 
POLYGONACEAB. 
RUMEX L. 
318. Bumex acetosella L. Field Sorrel. A common weed in waste 
places. 
319. Bumex hastaitaulus Baldw. Engelmann’s Sorrel. Rare as a weed 
along railways. 
320. Bumex Occident alis Wats. Western Dock. Rare in bogs. 
321. Bumex altissimus Wood. Peach-leaved Dock. Very common. 
322. Bumex verticillat us L. Swamp Dock. Scarce in marshes. 
323. Bumex mexicanus Meisn. Willow-leaved Dock. Common. 
POLYGONUM (Tourn) L. 
324. Polygonum aviculare L. Yard Knot Grass. Common everywhere. 
325. Polygonum aviculare Var. littorale (Link) Koch. Shore Knot 
Grass. With the above. 
326. Polygonum erectum L. Erect Knot Grass. Roadsides and waste 
places. 
327. Polygonum ramosissium Michx. Bushy Knot Grass. Dry Soil, 
not common. 
328. Polygonum tenue Michx. Slender Knotweed. Rather scarce in 
dry rocky places. 
329. Polygonum lapathi folium L. Pale Persicaria. Plenty in marshes. 
330. Polygonum muhlenbergii (Meisn.) Wats. Swamp Persicaria. 
In marshes. 
331. Polygonum pennsy Ivanicum L. Pennsylvania Persicaria, Com- 
mon in marshes. 
332. Polygonum hydropiper L. Smartweed or Water Pepper. Not 
abundant. 
333. Polygonum acre HBK. Water Smartweed. Scarce in marshes; 
Hills, 
334. Polygonum orientate L. Prince’s Feather. Scarce in waste places. 
335. Polygonum persicaria L. Lady’s Thumb. Abundant in marshy 
places. 
336. Polygonum hydropiperoides Michx. Mild Water Pepper. Abun- 
dant in marshy places. 
337. Polygonum virginianum L. Virginia Knotweed. Common in 
woodlands. 
