POLYGONACEOUS GENERA. 43 
glabrous, but the thin ocreæ appressed-villous, narrow, an inch 
long or more and longer than the short petioles; leaf-blades 
elliptic-lanceolate, acute, but scarcely acuminate, 5 or 6 inches 
long, the very lowest glabrous on both faces, the others rather 
densely but finely strigulose, the midvein beneath with longer 
stouter hairs gradually thickened from midway down to the 
base; very short peduncles copiously glandular-hispidulous with 
some long bristly hairs intermixed; spikes short and stout, 
barely 2 inches long, nearly 4 inch thick; bracts not strongly 
strigose-hairy. 
Aquatic state. Floating leaves long-stalked, the blade of a 
broad subcordate-lanceolate cut, merely acute, quite glabrous on 
both faces, upper leaves smaller, more lanceolate, not subcordate, 
the uppermost with traces of the pubescence of the terrestrial 
state; spikes long-stalked but otherwise as in the other state, 
save that both peduncle and bracts are glabrous. 
Local, as far as known, at Mountain Lake, a small pond in 
front of the U. S. Marine Hospital, San Francisco, where I 
several times collected the land form from 1888 forward. I never 
observed it as an aquatic with glabrous floating foliage; but the 
types of this state were obtained from the lake by my pupils 
Michener and Bioletti, in June, 1891. 
P. HESPERIA. Riparian, the slender stems 2 feet high from 
prostrate rootstocks inhabiting lake-shore mud, and forming 
dense colonies; herbage firm, light-green, apparently glabrous, 
the stem all the lower leaves truly so, except as to the leaf mar- 
gins, these closely and evenly spinulose-serrulate; petioles of 
these 2 or 3 inches long, the broadly lanceolate merely acute 
blades only 4 or 5 inches; reduced uppermost leaves with a sin- 
gle series of hair-points along all veinlets and abundant short 
appressed thick-based very firm-pointed hairs; short peduncles 
glandular-hispidulous, as also the bracts of the stout cylindric 
2-3-inch-long spikes. 
Margin of a lake near Searsville, San Mateo Co., California, 
20 Oct., 1902, ©. F. Baker, who distributes it under n. 1835. 
An exceedingly beautiful species by the contrasted vivid green 
