44 
pit. The spikes ripen from 2 to 6 fruit, most of the flowers being 
abortive. This species, especially in the submerged plant, is fur- 
nished with delicate reproductive buds which are formed at the 
ends of short lateral branches and by which it seems to be mainly 
propagated. The internodes are usually long and naked. 
Var. LATIFOLIUS, Morong. 
A rare form with submerged leaves 14-34 of a line wide, 
abruptly acute and 1-3-nerved. The glands more conspicuous 
than in the type. This was collected by Dr. Beardsley at Paines- 
ville, Ohio. 
A rare endemic species confined to Canada and the Northern 
United States. 
The original plant was collected by Dr. George Vasey near 
Ringwood, Ohio. It has since been found at Ottawa (F letcher), 
and on the Great Plains, Canada (Macoun); Barnet, Vt. (Dr. 
Blanchard); Lake Saltonstall, Conn. (O. D. Allen); Spot Pond, 
Stoneham, Mass., Lake Quinsigamond, Worcester, Mass. and 
Greenwood Lake, N. Y. (Morong). (Plate LI.) 
28. POTAMOGETOM LATERALIS, Morong, Bot. Gaz. v. 51 (1880). 
Stems filiform, much-branched, internodes usually long and 
naked. Floating leaves coriaceous, elliptical, obtuse at the apex 
and sloping at base into petioles 3-10 lines long, blades 4 or 5 
lines long by 1-2 lines broad, with 5-7 nerves deeply impressed 
beneath, usually in 1-3 opposite pairs which stand at right angles 
to the stem, found only on sterile shoots. Submerged leaves very 
narrow, linear, acute, 1-3 inches long and Y- line wide, 1-3- 
nerved, the lateral nerves very delicate and obscure, the midrib 
prominent and often with fine veins or cellular reticulations on 
each side of it, biglandular at base, but the glands few, small 
and often obsolete. Stipules small, hyaline, many-nerved, obtuse, 
deciduous. Peduncles as well as the floating leaves with a pecu- 
liar lateral appearanee, widely spreading at maturity, sometimes 
even recurved, thickened when in fruit, 4-15 lines in length. 
Spikes capitate or often interrupted, 3-4-flowered. Fruit obliquely 
obovate, about 1 line long by 34 line broad, lenticular, the back 
much curved and 2-grooved, the face arched and surmounted by 
the nearly sessile stigma; embryo oval in its curve, the apex 
