1920] Fernald,— Cardamine pratensis in America 13 
has had various names indicative of its habitat: C. palustris Peterm., 
C. paludosa Knaf, C. fontinalis Schur and C. pratensis, var. fossicola 
Godet. In contrast with the usually inundated habitats of this 
white-flowered variety we have the meadow- and turf-habitats of 
true C. pratensis, habitats well indicated by its name; and in Bailey’s 
Standard Cyclopedia of Horticulture the latter plant is said to be 
“also useful in drier places, as in rockeries." A few sheets in the 
Gray Herbarium of the indigenous plant have been referred by 
Schulz to var. dentata (Schultes) Neilreich, but whether or not the 
latter variety is distinguishable in Europe it is certain that our Amer- 
ican white-flowered bog plant cannot be satisfactorily regarded as 
two varieties. Schulz furtber maintains, in his discussion of var. 
palustris, that Kerner had been in error in considering that var. 
palustris had a distinct range from that of typical C. pratensis, say- 
ing *Eine besondere geographische Verbreitung besitzt demnach 
die Pflanze nicht, wie KERNER in Schedae ad Fl. Exs. Austro-Hung. 
III. 74 (1884) annahm." As an indigenous plant in America, true 
C. pratensis seems to occur only in Alaska. It is therefore clear that 
on this continent at least the two plants have decidedly different 
ranges. 
In the Arctic regions, extending south with us to the Aleutian 
Islands and to northeastern Labrador is a low extreme with usually 
pink petals and with the leaflets of the basal leaves linear to elliptic. 
This is var. angustifolia Hook. 
One other variation of Cardamine pratensis demands a special 
comment. This is the pink-flowered plant with “double” flowers, 
an old-fashioned garden plant which in eastern Massachusetts has 
become abundantly naturalized along Stony Brook in Middlesex 
County. This is forma plena Beck von Mannagetta. Although 
considered merely a form of true C. pratensis with numerous petals 
it Is noteworthy that the plant now naturalized along Stony Brook, 
as well as such European specimens as tbe writer has seen, has the 
leaflets unusually broad and more inclined to be petiolulate. 
Briefly summarized, these variations may be distinguished as 
follows: 
Lateral leaflets of the basal leaves with ovate to reniform blades: the ter- 
minal obovate to reniform, 0.35-3 em. long: stem 1.5-5 dm. high. 
Terminal leaflet of basal leaves distinctly crenate or dentate, with 3-9 
teeth: petals pink. 
Petals in a single series: latera! leaflets of the middle and upper cauline 
leaves linear to oblong, sessile or nearly so. ...C. pratensis (typical). 
