51 
rib and raised or slightly revolute margins. Fruit small, rarely 
more than a line in length and 34 of a line in breadth. Peduncles 
short, not more than 8 or 10 lines long at the most. This form 
commonly has a compact, bushy habit which is quite noticeable. 
Occurs in brackish and salt lakes of the prairie region, in Old 
Wives’ Lakes and Crawling Valley, south of the Hand Hills, 
Alberta, Canada (Macoun). This approaches: 
Var. occidentalis, Robbins, Bot. King’s Ex. 339 (1871). 
This as described by Robbins has some of the leaves similar to 
those of the preceding variety, but the peduncles often as much 
as 6 inches long, the fruit roundish-obovate, and the sides of the 
nutlet made.“ uneven by a central elevation partially surrounded 
by a shallow depression which is marginned by the raised lateral 
keel.” Ruby Lake, Nevada, 6,000 feet alt., (Watson); Shoshone 
Geyer Basin, Wyoming (Clifford Richardson). 
The species is rare in the United States, and was first detected 
by myself in the rapids above Niagara Falls in 1875, and since in 
similar rapids at Sault Ste. Marie, Mich. It is abundant in Seneca 
Lake, N. Y., and Mr. Hill has obtained it in Hemlock Lake, 
Western New York and Frankfort, Mich. It is more common in 
Canada, having been obtained by Prof. Macoun in brackish marshes 
on the sea coast at the Island of Anticosti, and in fresh water lakes 
and creeks in the Northeast territory, Manitoba and British Colum- 
bia. August. (Plate LVII.) 
34. PoTAMOGETON PECTINATUS, L. Sp. РІ. 127 (1753). 
Stems slender, from a running rootstock, much branched, the 
branches repeatedly forking, I to 3 feet in height, usually much 
stouter below. Leaves setaceous, attenuate to the apex, I-nerved, 
1-6 inches long, often capillary and without nerves. Gigantic 
forms were collected by Prof. W. К. Dudley in Lake Cayuga, from 
18 to 20 feet in length, and with leaves even 10 inches long. The 
form scoparius, Wallr., found in this country as well as in England, 
has numerous hair-like fasciculated leaves, very long and broom- 
like in appearance, whence the name. Stipules with sheaths 
which are white and scarious on the edges, %-ı inch 
long, and half as much free. Peduncles filiform, 2 to 12 inches 
long, the flowers in approximate or distant verticils, 2 to 4 flowers 
