58 MISSOURI BOTANICAL GARDEN. 
broad, basal lobes acute, acuminate, widely divergent, 
glabrous above, sparsely scabrous on _ the nerves 
below; scape usually simple, stout, often 6 to 8 cm. 
in diameter at the base; verticils mumerous, more 
or less approximate, 2 to 4 lower ones fertile; bracts con- 
nate at the base, lanceolate, long acuminate, the upper un- 
developed portion of the scape appearing comose with their 
projecting tips; staminate pedicels slender, ascending, 20 
to 30 mm. long, longer than the fertile; flowers large, the 
sepals broadly ovate, obtuse, 10 mm. wide, 15 mm. long; 
petals obovate, larger than the sepals; stamens very many, 
the narrow glandular pubescent filaments longer than the 
linear oblong anthers; achenia 2 to 3 mm. long, narrowly 
quadrate obovate, winged on both margins, with a short 
slender, oblique beak, and a prominent sub-epidermal 
resin passage on each side above; fruiting head large, 15 
to 30 mm. in diameter.— A South American species estab- 
lished as a ballast plant in California and North Carolina. 
Specimens examined from California (J. A. Sanford, July 
1893, Stockton); North Carolina (Gerald McCarthy, 
September, 1888). — Plate 29. 
SPECIES FROM MExIco. 
§§ Fluitantes: stamens 12 or 18. 
S. DEMERSA 0. sp. 
Submerged aquatic; the floating phyllodia linear atten- 
uate, 2 to 6 dm. long, 10 to 15 mm. thick at the base, taper- 
ing gradually to the obtuse apex; scape simple, weak, rising 
to the surface of the water, usually 20 to 30 cm. long; 
bracts scarious, deeply connate, acute, 3 to 5 mm. long, 
soon evanescent; verticils 4 to 6, the lowest fertile; fertile 
pedicels thickened, 10 to 35 mm. long, at length reflexed; 
sterile pedicels slender, erect-spreading, 10 to 20 mm. long, 
the flowers at length deciduous, filaments dilated, glabrous, 
twice as long as the sub-orbicular anthers; fruiting head 
5 to 6 mm. in diameter, sub-globose; achenium obovate, 
p> £ 
32 
