338 BOTANY. 



cies ranges from Florida to Canada and the Slave River ; the variety occur- 

 ring along the Great Lakes. On the Truckee River, Nevada ; 4,000 feet 

 altitude; July, in flower. (1,135.) 



PoTAMOGETON PUSILLUS, L., Var. vtLGAEis, Fries. (I) Diflfering from 

 the ordinary form, especially in the revolute and consequently subulate form 

 of the leaves produced by desiccation, resembling in this respect P. ccBspitosus, 

 Nolte. The species is reported from the Northern States to Canada, Hud- 

 son's Bay and the Saskatchewan. Bear River, in the Uintas ; 8,000 feet 

 altitude; August, in fruit. (1,136.) 



Subvar. intekeuptus, Robbins. Leaves less rigid and taper than in the 

 last, and with the midrib veiny. Parley's Park in the Wahsatch; 6,000 feet 

 altitude; July, in flower and fruit. (1,137.) 



PoTAMOGETON PECTiNATUS, L. The typical form ; the apex of the em- 

 bryo little incurved. Western Florida and along the coast northward ; from 

 Lake Champlain to Wisconsin, through Canada to Hudson's Bay, and west- 

 ward to the Rocky Mountains, (Drummond ;) Oregon, (Scouler ;) Colorado ; 

 California; New Mexico (Wright) and Sonora. In still brackish water in 

 Thousand Spring Valley, Nevada ; 6,000 feet altitude ; September, in fruit. 

 (1,138.) A doubtful form, the whole plant and especially the peduncles un- 

 usually slender, was also found in the Humboldt River, near its sink, in brack- 

 ish running water ; 4,000 feet altitude; August, scarcely in flower. (1,139.) 



Var. With sparse long and rather broad (I") leaves. In a cold fresh- 

 water stream in Ruby Valley, Nevada ; 6,000 feet altitude; July, with imma- 

 ture fruit. (1,140.) 



Var. Leaves 3-nerved, still broader and longer, intermediate between 

 the last form and the following one. In the Lower Humboldt River, with 

 the doubtful form above ; barren stems. (1,141.) 



Var. (?) LATiFOLius, Robbins. Stem thicker; leaves numerous, short 

 (1-2',) flat, broad (1-2",) 3-5-nerved, reticulate with many cross-veins, older 

 ones obtuse, the younger acute or acuminate ; sheaths large, many-nerved, 

 with scarious margins ; stipules scarious, obtuse, shorter than the sheaths ; 

 peduncles short (1-3';) fruit slightly smaller, somewhat corrugated when 

 dry ; style long ; embryo more incurved.— Agreeing sufficiently well with the 

 brief specific character given by Fries to his P. zosteraceus, but it differs es- 

 sentially from parts of his detailed description, ("Planta ingens longissima; 

 folia siccatanigrescentia; ligula elongata demum fissa; pedunculus longissi- 



