68 NORTH AMERICAN FLORA [VoLUME 17 
obtuse ; anthers 3, subsessile, oblong, alternate, with the sepals, 2-celled, extrorse ; pistil- 
late flowers sessile ; hypanthium lanceolate flask-shaped ; sepals 3, minute, resembling small 
papillae; stigmas 3, sessile, filiform, with 2 rows of papillae; capsule about 5 mm. long; 
seeds about 20. 
TYPE LOCALITY: Martinique. 
I DISTRIBUTION : On the bottoms of bays, from Martinique to St. Thomas, Porto Rico, and 
amaica, 
ILLUSTRATION: Bih. Sv. Vet.-Akad. Handl. 912: p/. 1-3. 
2. Halophila Aschersonii Ostenf. Bot. Tidsskr. 24: 239. 1902. 
Horizontal stem or rhizome creeping, slender, its internodes 1-3 cm. long; scales in 
pairs at the nodes, lanceolate, the lower horizontal, the upper erect, pubescent; erect shoots 
1-4 cm. long, bearing 1 pair of obovate scales at the middle, in the axils of which often 
arise secondary rhizomes, and 2 pairs of leaves at the summit; leaves distinctly petioled ; 
petioles 3-5 mm. long; leaf-blades elliptic, 8-20 mm. long, 4-8 mm. wide, obtuse at both 
ends, hispidulous, densely spinulose-serrate on the margins, 3-ribbed, with 3-5 pairs of 
transverse veins, thin; pistillate flowers sessile in the axils of the upper pairs of leaves, 
surrounded by two lanceolate acute bracts; hypanthium flask-shaped; body ovoid, 2 mm. 
long; tube slender, about 5 mm. long; sepals minute; stigmas 2 or 3, 15-30 mm. long; 
staminate flowers unknown, 
TYPE LOCALITY: St. Croix, West Indies. 
DISTRIBUTION : Muddy bottoms of bays at a depth of about 1m., Danish West Indies, Porto 
Rico, and Jamaica. 
ILLUSTRATION: Bot. Tidssk. 24: 239. f. 
3. Halophila Engelmanni Aschers. in Neumayer, Anleit. Wiss. 
Beob. 368. 1875. 
Horizontal stems or rhizomes slender, creeping ; internodes 2-4 cm. long; scales broadly 
obovate, glabrous, 3-4 mm. long; esect shoots 2-4 cm. long, with 1 pair of broadly obovate 
scales at the middle and usually 3 pairs of leaves at the summit; leaves subsessile or very 
short-petioled ; petioles 2mm. long or less ; leaf-blades oblong or linear-oblong, usually acut- 
ish at both ends, 1-3 cm. long, 3-6 mm. wide, rather thick, faintly 3-ribbed and with 6-8 pairs 
of lateral veins, reticulate-roughened, densely spinulose-serrate on the margins; pistillate 
flowers in the axils of the leaves, enclosed by two lanceolate acuminate bracts; hypanthium 
flask-shaped ; body ovoid, 3-4 mm. long; neck about 5 mm. long; sepals minute; stigmas 
3, filiform, about 3 cm. long; staminate flowers unknown. : 
TYPE LOCALITY: Florida. . 
DISTRIBUTION : Bays and creeks, Florida and the Bahamas. 
2. VALLISNERIA L. Sp. Pl. 1015. 1753. 
Aquatic dioeceous submerged plants, almost stemless with perennial stoloniferous root- 
stocks. Leaves basal, ribbon-like, floating. Staminate flowers numerous, crowded on a 
spadix, enclosed in a 2-3-parted spathe, detached at maturity and floating and expanding on 
the surface of the water; perianth of 3 sepals; stamens 1-3, usually 2. Pistillate flowers 
solitary, at the ends of long slender scapes, floating on the water, subtended by a tubular 
2-cleft spathe; hypanthium linear-cylindric; sepals and petals 3. Ovary 1-celled, with 3 
parietal placentae. Stigmas 3, 2-lobed. Ovules numerous, orthotropous. Fruit cylindric, 
indehiscent. 
Type species, Vallisneria spiralis lL. 
Stigmas 2-cleft for less than half their length; sepals 2-3 mm. long; pistillate peduncles usually 
spiral-twisted in fruit; leaves 3-8 mm. wide. . 1. V. spiralis. 
Stigmas 2-cleft to near the base; sepals 5-6 mm. long; pistillate peduncles 
scarcely spiral-twisted in fruit ; leaves 6-20 mm. wide. 2. V. americana. 
1. Vallisneria spiralis L. Sp. Pl. 1015. 1753. 
Leaves thin, linear, 1-5 dm. long, 3-8 mm. wide, obtuse or acutish, usually minutely 
denticulate, especially towards the apex; peduncles of the staminate plant 1-5 cm. long; 
