54 MISSOURI BOTANICAL GARDEN. 
ascending, 6 to 12 mm. long; sterile pedicels 10 to 15 mm. 
long; stamens about 12, the dilated pubescent filaments a 
little longer than the short oblong anthers; fruiting head 
about 12 mm. in diameter; achenia oblong obovate, 3 mm, 
long, broadly winged on both margins, smooth or faintly 
unicostate, and with 2 or 3 resin passages on each side, 
beak short and oblique.—Margin of ponds in South Car- 
olina. Collected by M. A. Curtis in South Carolina 
(Engelm. Herbarium). Related to éeres and cristata.— 
Plate 23. 
S. reres S$. Wats. in A.Gray, Man. Ed. 6, 555 (1890). 
Monoecious, with acute, attenuate, terete, usually nodose 
phyllodia 10 to 30 em. long, very rarely bearing a short 
linear blade; scape slender, erect, simple, 15 to 45 cm. 
high; bracts ovate, obtuse, 3 mm. long; verticils few, 1 
to 8, 1 or 2 flowers of the lowest fertile; fertile pedicels 
slender, ascending, 10 to 25 mm. long, exceeding the ster- 
ile; flowers small, 12 to 15 mm. across; stamens 12, the 
filaments dilated, pubescent, shorter than the anthers; 
mature achenium rounded-obovate, 2 mm. long, with a 
short, erect beak, the ventral margin wing-angled, dorsal 
margin and _ sides crenately several- (7 to 11) crested; 
fruiting head 8 to 12 mm. in diameter.—In shallow water, 
Massachusetts to South Carolina. Mature achenia collected 
only by Walter Deane, at Hyannis, Mussachusetts, August, 
1888. The immature achenia are dark brown, and barely 
costate laterally. The fruits usually ripen under water, 
and do not then assume the same characters as when ripen- 
ing above water.— Plate 24. 
Specimens examined from Massachusetts (Farlow, 1881; Brewster) ; 
New York (E. 8. Miller, Wading River, Long Island, 1871); New Jersey 
(Torrey, 1833, pine barrens). Specimens marked A, collected in North 
Carolina by M. A. Curtis, are intermediate between this species and 
macrocarpa. They have the habit of ¢eres, but with larger achenium 
(2.5 mm.) with smooth sides, and more oblique beak. 
+ + + + Achenium short obovate, with a short lateral beak; leaves 
lanceolate, entire; filament slender, glabrous; bracts connate, densely 
papillose. 
28 
