528 
Such conditions, however, when the characteristic ciliate perianths 
are wanting, can usually be distinguished from any state of P. 
rivularis by the more oblong, more distinctly marginate, dorsal 
leaf-lobes, and by the longer and narrower ventral lobes and un- 
derleaves, which are more pronouncedly caudate at the base. 
The above revision is based, outside of our own collcctions in 
California, chiefly upon the rich representation of this genus in the 
herbarium of Professor Underwood, and upon the specimens in 
the herbarium of Columbia University. We further gratefully 
acknowledge our indebtedness to the Philadelphia Academy of 
Sciences, for the loan of the Schweinitz collection; to Dr. A. W. 
Evans for the privilege of examining specimens in his own her- 
barium and that of Yale University, and to W. H. Pearson, Esq., 
of Knutsford, Cheshire, England, for the loan of the type of Po- 
rela Bolanderi. 
COLUMBIA UNIVERSITY, DEPARTMENT OF BOTANY, 
November 13, 1897. 
A new Species of Wild Ginger hitherto confounded with Asarum 
Canadense L, 
By Evucene P. BICKNELL. 
(PLATES 316, 317.) 
It has certainly much significance in its bearing on the study of 
our common flora that a plant so noteworthy as the familiar wild 
ginger, and supposedly so well understood, should now reveal 
itself as embracing two perfectly distinct species. Both plants are 
common and widely distributed, but they are so much alike in 
general appearance that it is scarcely a matter of surprise that they 
have held their secret so long. Agreeing in main features through- 
out, they share the same general form of rootstock, leaf and flower, 
are similar in habit of growth, and bloom at the same time. The 
differences between them are, in fact, no greater than might fairly 
measure the variation of a single species, and that they are of 
higher import has been learned only by careful field study con- 
tinued through several seasons, 
