1900] Wiegand, — Varieties of Potamogeton and Spiraea 103 
Lakes and rivers of Central New York. It has been found in most 
of the ponds of Oswego County and in Cayuga Lake, as well as in 
other smaller lakes and streams about Ithaca. 
While collecting last summer in the Adirondack Mountains my at- 
tention was called to the spiraeas of that region by the peculiar appear- 
ance of their foliage. Instead of the narrow dark-green and finely 
serrate leaves of the S. salicifolia found about Ithaca, the plants all 
possessed broadly elliptical and coarsely dentate leaves of a much paler 
or yellowish-green color. This color of the foliage was often quite 
marked as was also that of the flowers which on some plants was of a 
bright pink or rose-color. Closer inspection showed that the panicle, 
which in the ordinary form is densely tomentulose, was in these plants 
almost, if not quite, glabrous, but differences sought in the floral struc- 
tures were not found and probably do not exist. A study of herbarium 
material leads me to the belief that S. salicifolia may be separated into 
two quite marked forms along the lines noted above. These may be 
distinguished somewhat as follows : 
S. SALICIFOLIA L. Leaves broadly or narrowly oblanceolate, acute, 
dark-green, finely and sharply serrate ; inflorescence broadly pyramidal, 
the branches, pedicels, and calyx densely tomentulose ; flowers white. 
Quite widely distributed over the north-eastern United States, our 
specimens coming from various portions of New York, Canada, and 
from as far south as North Carolina. 
Var. LATIFOLIA Ait. Leaves obovate or elliptical, much broader and 
often shorter than in the last, scarcely acute, coarsely dentate-serrate, 
pale yellowish-green ; inflorescence, broadly pyramidal, nearly glabrous, 
and with a yellowish tinge ; flowers white or rose-color. 
Also widely distributed in the same region, but seemingly more 
common in New England. I have seen specimens from Maine, Massa- 
chusetts, Connecticut, Virginia, and in New York State from Oswego 
County, Chemung County, and the Adirondacks. 
I should be tempted to consider these forms distinct species if it 
were not for some peculiar specimens collected last fall near Ithaca, 
which seem to be rather intermediate in nature. More ample material 
may still prove them to be distinct. At any rate it must be admitted 
that in the extreme forms they are strikingly unlike. 
It still remains an open question whether our white-flowered Ameri- 
can plant is distinct from the European form with rose-colored flowers. 
Some European authors, among whom are Koch and Dippel, consider 
them distinct, and take up for the white-flowered form the name S. alba 
