235 
Several forms occur in Brazil, distinguished mainly by the 
length of the peduncle, the one regarded by Hegelm. as the type 
with peduncles 3-5 mm. long, and fruit somewhat larger than 
in ours. 
New York to Washington, D. C., west to Missouri, Ar- 
kansas, Louisiana and Texas, Central and South America. 
2. C. marginata. Torr. Bot. Whip. Ex. 135 (1856). Hegelm. 
Verhand. Bot. Brand. 9, 12 (1867.) 
Amphibious, usually floating, sometimes growing in mud. 
Submerged leaves linear, one-nerved, running gradually into the 
emersed, which are oblanceolate or spatulate, and three-nerved, the 
blade 4-6 mm. long and about 2 mm. broad. Styles as long as or 
shorter than the fruit, reflexed, deciduous. Fruit 1-114 mm. long 
and 14%4-134 mm. broad, with conspicuous membranous wings 
and divergent lobes. . - 
Peculiar to the Pacific coast from Arizona to California. Also 
attributed to Chili. 
3. C. Nuttall, Torr. Bot. Whip. Ex. 135 (1856). 
C. pedunculosa. Nutt. Trans. Am. Phil. Soc. Vol. V, n. s. 140 
(1837) not Arnott nor C. pedunculata, D.C. 
A small terrestrial species growing in moist grounds. Leaves 
all spatulate, three-nerved, the blade 3 or 4 mm. long and 1-1% 
mm. broad, often finely wrinkled or granulated, apparently with- 
out stellate scales. Fruit thick, deeply emarginate at apex and 
base, 3-} mm. in length and /-1 mm. in breadth, the lobes with 
narrow marginal keels. Styles erect, longer than the fruit, decid- 
uous. This and the following species are peculiar in bearing the 
fruit on reflexed peduncles and burying it in the mud. 
First discovered by Nuttall in Arkansas and described by him 
under the name C. pedunculosa, but, unfortunately, the name had 
been already preoccupied.. It extends down the Mississippi to 
Louisiana. (Hale, Langlois.) 
4. C. sepulta. S. Watson. Proc. Am. Ac. 14, 298 (1879.) 
A small terrestrial prostrate species, similar in general ap- 
pearance and habit to the preceding. Leaves linear, one-nerved, 
3-5 mm. long, somewhat wrinkled or granulated below, as in 
C.Nuttallit,and apparently without stellate scale. Styles elongated, 
reflexed, soon deciduous, Fruit thick, about 34 mm. long and 
