216 AMERICAN MIDLAND NATURALIST 
Genus PERSICARIA Tragus, (1531), in Brunfels’ Herb. Viv. 
Icones. Brunfels App. p. 18 (1531), also Tragus do. p. 161 (1531), 
also Pulicaria Brunfels, (1531), etc., ete. 
Persicaria ‘Tournefort, (1694). Els. Bot., p. 410, (1700) Inst. 
Rei. Herb., p. 509, also Linn., (1737) Gen. Pl., p. 35. Polygonum 
Linn., (1754) Gen. Pl., p. 170. in part; also Sp. Pl. p. 359 in’part. 
Persicaria Trew in Herb. Black., (1754), Tab. 118 and 119, 
Hill, (1756) British Herball, p. 486, Shaw, (1757) Trav. and Obs. 
Lev.,~ Collect. -:p:'466., ‘Morandi, (1760). Hist: (Pl. Pract parse 
Adanson; (1763); Fam, des Pl vol.-H., p276: 
Section. POTAMOCALLIS. 
Perennial plants typically amphibious with rose- colored to 
crimson flowers, (never white). 
‘\ 
Subsection I., EMERSAE. 
Plants never having spreading herbaceous borders to the 
ochreae in any of the phases. 
PERSICARIA AMPHIBIA (Linn.) S. F. Gray, (1821) Nat. Arr. 
Ba. blatvols LE py 208s 
Since the last time I made a study of the European species 
in the National Herbarium a larger number of specimens are 
now available. Though there is some variation in. the plants both 
terrestrial and aquatic, | am more than ever persuaded that P. 
amphibia is not found in America. Whatever resemblance there 
may be in the aquatic phases to our well known plants either 
P. canadensis or P. fluitans or P. mesochora or even the aquatic 
plants that are to be referred to P. coccinea, there can be but 
one reason advanced for their identity with it, and that is at most 
a negative one. P. mesochora Greene, can .at once be dismissed 
because in its spring terrestrial phase it has the spreading ochrea 
borders and wider lanceolate leaves of the terrestrial phase. No 
European plant has as yet been found with these borders! And 
yet P. mesochora seems in every way the nearest relative of our 
American plants to the real European P. amphibia, superficially 
observed. 
P. fluitans Eaton and P. canadensis Greene have not it is true 
been found in their terrestrial phases. There seems much reason 
to suspect that they are normal aquatic without terrestrial phases, 
because of their deep water habit of growth. Moreover, I have 
