34 NORTH AMERICAN FLORA [VoLuME 17 
2. Naias flexilis (Willd.) Rost. & Schmidt, Fl. Sedin. 382, 1824. 
Caulinia fexilis Willd: Mem. Acad. Berlin 1798: 89. 1801. 
Naias canadensis Michx. Fl. Bor. Am. 2: 220. 1803. 
Natas flexilis robusta Morong, Bot. Gaz. 10: 255. 1885. 
Stem slender, branched, often dichotomously so, elongate or sometimes short and 
densely bushy; leaves all submerged, linear, 0.8-2.5 cm. long, 0.5 mm. wide, or some- 
times wider, erect or often recurved; marginal teeth 20-30, prominent; leaf-sheaths 
rounded, not auriculate, toothed; flowers monoecious; staminate flower 2.5-3 mm. long, 
the anther 1-celled; pistillate flower 1-2.5 mm. long, the stigmas 2-4, usually 3, subulate; 
seed ellipsoid, apparently smooth and shining, but under a strong lens reticulate with 
minute 6-sided areolae. 
TYPE LOCALITY: Pennsylvania. 
DISTRIBUTION : Quebec to British Columbia, south to Florida and Texas. 
ILLUSTRATIONS: Britt. & Brown, Ill. Fl. £ 180; Mem. Torrey Club 3?: £1. 66; E. & P. Nat. 
Pfl. 21: f 165 4,; Trans. Linn. Soc. 11.5: pl. 40, f. 92-98. 
3. Naias guadalupensis (Spreng.) Morong, Mem. Torrey 
Club 3’: 60. 1893. 
Caulinia guadalupensis Spreng. Syst.1: 20. 1825. 
Naias flexilis fusiforme Chapm. F1. S. U.S. 444. 1860. 
Naias flexilis guadalupensis A. Br. Jour. Bot. 2: 274, 1864. 
arts anal A. Br. Sitz.-ber. Ges. Nat. Freunde Berlin 1868: 17. 1868.— Bot. Zeit. 26; 510. 
6 
Naias microdon guadalupensis A. Br. loc. cit. 1868. 
Naias microdon curassavica A. Br. loc. cit. 1868. 
Naias guadalupensis curassavica Magnus & Rendle, Symb. Ant. 4: 74. 1903. 
Stem slender, branched; leaves all submerged, linear, 1-2.5 cm. long, 0.4-1.7 mm. 
wide, acute or obtuse at the apex, and usually tipped with 1 or 2 spines, sheathing at the base ; 
marginal teeth inconspicuous, 20-40, often apparently wanting; leaf-sheaths sloping or 
rounded, not auriculate, spinulose; flowers monoecious; staminate flowers 2-3 mm. long, 
the anthers 4-celled; pistillate flowers 2-3 mm. long; mature fruit crowned with 2 or 3 stig- 
mas and usually with 1 or 2 spiny, sterile, stigmatic processes, thus apparently with 3-5 
stigmas; seeds ellipsoid, reticulate with numerous 4-sided areolae. 
TYPE LOCALITY : Island of Guadeloupe. 
DISTRIBUTION: Pennsylvania to Oregon, south to Florida, Mexico, and Central America ; 
Cuba; Porto Rico ; Jamaica; Guadeloupe. 
ILLUSTRATIONS : Britt. & Brown, Il. Fi. f. 181; Mem. Torrey Club 3?: p/. 67. 
4, Naias conferta A. Br. Sitz.-ber. Ges. Nat. Freunde Berlin 1868: 17. 
1868.— Bot. Zeit. 26: 510. 1868. 
Naias arguta conferta A. Br. Jour. Bot. 2: 277. 1864. 
Naias Wrightiana A. Br. Sitz.-ber. Ges. Nat. Freunde Berlin 1868: 17. 1868. 
Natas Wrightiana laxa A. Br. loc. cit. 1868. 
Stem slender, much branched, elongate or shortened ; leaves all submerged, 1.2-2 cm. 
long, 0.4-0.5 mm. wide, acute, at the apex and tipped with a single subulate spine ; leaf- 
margins with 16-40 conspicuous triangular teeth, the teeth spinulose; leaf-sheaths rounded, 
’ not auriculate, with spiny teeth; flowers monoecious; staminate flower of a single 4-celled 
anther; pistillate flower naked, ovoid; stigmas 2, and without intermingling sterile stig- 
matic processes; fruit narrowly ellipsoid, 1-2 mm. long; reticulations of the seed-coat 
numerous, 4-sided. 
TYPE LOCALITY : Cuba. 
DISTRIBUTION : Cuba, and in tidal creeks, Milton, Florida. 
ILLUSTRATION: Trans. Linn. Soc. II. 5: pl. 40, f. ‘68 77 (68-74, as N. Wrightiana). 
5. Naias gracillima (A. Br.) Magnus, Beitr. Gatt. Najas 23. 1870. 
Natas indica gracillima A. Br.; A. Gray, Man. ed. 5. 681, 1868. 
Stem slender, capillary, much branched; leaves all submerged, capillary, apparently 
though not truly terete, opposite or fasciculate, 1-2.8 cm. long, scarcely 0.2 mm. wide; 
margins with about 20 minute teeth, the lower part essentially entire; sheaths sharply 
