99 
855. R. acetocella, L. Field or Sheep Sorrel. 
In waste places, old fields, etc.; very abundant. June — September^ 
occasionally as early as May 15th. 
POLYGONUM, Tourn. Knotweed. Polygonum. 
856. P. aviculare, L. Knot-grass. Door-weed. Goose-grass. 
Near buildings, and everywhere in waste places. July — September. 
857. P. erectum, L. Erect Knot-grass. 
P. aviculare , L., var. erectum , Roth. 
Rich and moist soil in shaded places ; frequent. July — August. 
858. P. ramosissimum, Michx. 
Lake shore at Evanston ; rare. July, 1884-’87. Near Lake Calumet. 
Sandy shore near South Chicago, Bastin ! (B.) 
859. P. tenue, Michx. 
Rare. September. (B.) 
Hyde Park, Bastin. Sand hills, near Whiting, Ind., Hill / 
^860. P. lapathifolium, L., var. incarnatum, Watson. 
7 P. incarnatum. HU. 
i/C ne- 
Marshes and borders of lakes and ponds ; common. July — August. 
During the season of 1886, the white-flowered form prevailed, and 
was common at Lake Hyde, Ind. 
The flowers were mostly flesh- colored during 1887. 
861. P. pennsylvanicum, L. 
Moist banks and ditches, roadsides and moist places ; frequent south 
and west. July — September. 
862. P. amphibium, L. Water Persicaria. 
Generally in the form of Var. aquaticum, Willd. 
Chiefly in shallow water south; infrequent elsewhere. July — August. 
868. P. muhlenbergii, Watson. 
P. amphibium , L., var. terrestre, Gray. 
Muddy banks of the Desplaines river, near Riverside. On the prairies 
southeast of the Bridewell; infrequent. Miller’s and Berry Lake, 
Ind. Evanston, Boltwood. Sandy borders of sloughs, Pine 
Station, Ind., Hill. (B. P.) 
864. P. orientale, L. Prince’s Feather. 
Sparingly escaped from cultivation. Spontaneous in gardens. 
August. 
865. P. persicaria, L. Lady’s Thumb. Heart-weed. 
Moist waste places; common, locally abundant. June — September. 
