53 
Fruit about 2 lines long by 1% lines wide; back usually without 
a keel, the lateral ridges rounded; face gibbous at the top; style 
facial, rather long, erect or slightly recurved; embryo apex point- 
ing slightly inside of the basal end. Often in the fruit the curve 
of the back rises at the top almost as high as the style, making 
that appear as if on the face, a peculiarity which occurs sometimes 
in pectinatus also. It is a question whether this form is the same 
as Ше broad-leaved forms of fabellatus, but it differs from that 
species not only in fruit characters, but in having many short 
lateral branches, shorter and more obtuse leaves, and a stouter 
and stricter stem. 
The plant described by Robbins was collected in the *running 
brackish waters of Humboldt River below Humboldt Lake," Ne- 
vada. A fine specimen is in the Herb. of Mr. I. C. Martindale, of 
Camden, New Jersey, collected by Mrs. R. M. Austin in Goose 
Lake, Northeastern California, in Sept. 1884. The fruit here de- 
scribed is taken from that specimen. (Plate LIX.) 
36. PorAMOGETON INTERRUPTUS, Kitaibel; Schultes, CEst. Fl. Ed. 
2, 328 (1814), fide Ar. Bennett. 
P. flabellatus, Babington, Man. Bot. Ed. 3, 343 (1851). 
From a running rootstock which often springs from a small 
tuber. Stems stout, branching, 2-3 feet in height, the branches 
spreading like a fan. Leaves linear, obtuse or acute, 3-5 inches 
long, I line or a little more in width, 3-5-nerved, with many trans- 
verse veins.* Narrow, I-nerved leaves occur on some plants, and 
these are acuminate, much like those of P. pectinatus. Stipule on 
the adnate part %-ı inch long, without scarious edges, or nar- 
rowly scarious, the free part shorter and scarious, obtuse. Ре- 
duncles 1-2 inches long. Spikes slightly interrupted. 
Our United States plants have never been observed in fruit, 
but I am able to give the fruit characters from specimens kindly 
* It should be noted that Mr. Fryer regards these broad leaves as belonging mostly 
to sterile or autumnal shoots. Normally, as he describes the leaves, they are narrow 
or setaceous like those of pectinatus. The chief difference between the species and 
N in his opinion, lies in the fruit. But as these broad leaves are the onl 
n und in the United States, and as they are the kind i SEE attributed to 
the species ü Prof, Babington, I can only pay regard to them in this account of our 
species. 
