4, P, tenuifolius Kaf, Stems mostly simple, the floating leaves 4-8 cm, 
indistinct ovetiole, firm but hardly leathery; submerged leaves sessile or 
nesrly so, linear-elliptical or linear-oblanceolate,mostly acute at both 
ends, similsr to the floating leaves in size and shape but thinner; stipules 
20-35 mme long; spikes cylindrical, reddish, 12-25 mm, long, about 8 mn, 
thick at maturity on peduncles 4-10 cm. long, somewhat thicker than the 
stem; nutlets smooth, 2-2.5 mm, long, S-kecled, the middle keel narrowly 
winged. (Pe alvinus 1B), 
In mountain streams emptying into Lake Pend Oreille, Leiberg 194, 
——— oe 
5 P. epinvdrus nal. Stems simole or branched, compressed, slender, the 
blades of the floaving leaves narrowly oval, 5-6 em. long, 12-20 mm, vride, 
nostly obtuse, the apex narrowed at the base and attenuate into vetioles 
subecual to the blaces or longer; submerged leaves sessile, numerous, thin, 
linear or linear-lanceolste, mostly Senerved, with a cellular reticulation 
ets 
alon,, the midrib, 6-12 cm, long, cormonly S-6 mn, wide; spikes usually 
several, cylindrical, l-4 cm. long, S-9 mm, .ide in fruit, on stout peduncles 
om om, longs; nutlets 3 mn. brosd, pitted, 3ekceled,. 
Taal pik , 
Shallow water in bog near ay tey Priest ie, “pling. The var, Nuttallii 
errr, ~l psa 
mm es 
(C. 2 S.) Fern.e, smaller in leaf and fruit, is to be exvected, 
; 
; 
5 
7 
