238 
marked wing on the lobes which runs into the apical notch and 
all around the margins, 1!-12 mm. long and 1-1; mm. broad. The 
fruit is thinner than in C. verna, and the lobes less divergent, the 
groove about as deep. Collected by Prof. E. L. Greene near 
Donner Lake, Sierra Nevada, California. 
9 C. Bolanderi. Hegelm. Verhand Bot. Brand 10, 114 (1868 ?). 
Usually more branching, with larger stems and leaves than in 
C. verna, but similar to that species in general appearance and 
habit. Floating leaves obovate or rhombic-obovate. Fruit or- 
bicular or slightly obovate, 1-114 mm. in diameter, or sometimes 
a little longer than broad, the lobes scarcely winged, with sharp 
or obtuse closely approximated margins. Styles twice as long as 
the fruit, erect, persistent or subpersistent. A Pacific coast plant, 
occurring at Vancouver’s Island, and other places in British 
Columbia, Oregon, (Hall No. 460), Washington, Placer County, 
(Bolander) and other places in California. 
10. C. autumnalis. L. Sys. Nat. 2,52, No. 13 (1767). 
C. angustifolia. Woppe. Bot. Tasch. 155 (1792). 
C. virens. Gold. Act. Mosq. 5, 119 (1817). 
Plant entirely submerged, very bright green when fresh, often 
growing in rapids. Leaves entirely destitute of stellate scales, 
crowded on the stem, linear-lanceolate, broader and clasping at 
the base, retuse or bifid at the apex, one-nerved, 10-15 mm. long. 
Styles about as long as the fruit, reflexed and soon deciduous. 
Fruit sessile or occasionally on a minute peduncle, slightly nar- 
rower than long, or orbicular, 1-2 mm. in diameter, the lobes with 
a deep groove between them which extends half way to the centre 
of the fruit, and broad wings on the margins. 
Extensively diffused in northern regions. Common in Can- 
ada and British Columbia. It occurs in western Massachusetts, 
(Gr. Man. Ed. 6) Lake Champlain (Pringle), Sault Ste. Marie 
(Morong), South Colorado (Brandegee), and Harney Valley, 
Oregon (Howell). 
11. C. peploides. Nutt. Trans. Phil. Soc. n. s. 5, 141 (1837). 
C. Drummondi. Hegelm. Monog. 60 (1864). 
A small species, creeping in mats 2-4 cm. upon moist 
ground, often under the shade of dwelling houses. Leaves all 
obovate or oblanceolate, 2-5 mm. long, %-3% mm. broad, the 
