50 NORTH AMERICAN FLORA [VoLUME 17 
11-16 mm. in diameter; achenes broadly cuneate, 2-2.5 mm. long, the beak stout, the 
dorsal wing thin. 
TYPE LOCALITY: Louisiana. 
DISTRIBUTION: South Dakota to Delaware, Alabama, and New Mexico. 
ILLUSTRATIONS: Britt. & Brown, Ill. Fl. f 192; Engler, Pflanzenreich 45: /, 1?, A, B (fruit). 
5. Lophotocarpus spongiosus (Engelm.) J. G. Smith, Rep. Mo. Bot. 
Gard. 11: 148. 1899. 
Sagittaria calycina spongiosa Engelm. in A. Gray, Man. ‘ed. 5. 493. 1867. 
Plants submerged ; leaves 1-2 dm. tall, the petioles stout and spongy, conspicuously 
nodose-septate, the blades spatulate, oblong, elliptic, sagittate or hastate, 1-3 cm. long, the 
basal lobes, when present, more or less falcate; scapes about one half as long as the leaves 
or less, the inflorescence simple, with one or two whorls; sepals broadly ovate or orbicular- 
ovate, becoming 10-12 mm. long; fruit-bearing pedicels very stout, 1-2 cm. long, or rarely 
longer; fruit-heads 7-10 mm. in diameter; achenes cuneate, 2-2.5 mm. long, the beak 
short, at the top of the achene-body, the dorsal wing thin. 
TYPE LOCALITY: Northeastern Atlantic States. 
DISTRIBUTION : New Brunswick to Virginia. 
ILLUSTRATION: Rep. Mo. Bot. Gard. 11: fl. 56. 
6. Lophotocarpus spathulatus J. G. Smith, Rep. Mo. Bot. 
Gard. 11: 149. 1899. 
Plants aquatic; leaves less than 1 dm. tall, the petioles stout, not conspicuously sep- 
tate, the blades linear or spatulate dilations at the top of the petioles, or wanting; scapes 
shorter than the leaves, stout but weak, the inflorescence with but one whorl; sepals ovate 
to orbicular-ovate, becoming 3 mm. long; fruit-bearing pedicels stout, about 1 cm. long or 
less; fruit-heads 5-6 mm. in diameter; achenes cuneate, 1.5-2 mm. long, the beak much 
below the top of the achene-body, the narrow dorsal wing thin. 
TYPE LOCALITY: Newburyport, Massachusetts. 
DISTRIBUTION: Massachusetts. 
ILLUSTRATION: Rep. Mo. Bot. Gard. 11: 62.57. 
7. Lophotocarpus guayanensis (H.B.K.) J. G. Smith, Rep. Mo. Bot. 
Gard. 6: 61. 1894. 
Sagitlaria guayanensis H.B.K. Nov. Gen. & Sp.1: 250. 1816. 
Echinodorus guyanensis Griseb. Fl. Brit. W. Ind. 505. 1864. 
Lophiocarpus guyanensis Micheli, in DC. Monog. Phan. 3: 62. 1881. 
Lophotocarpus guyanensis typicus Buch. in Engler, Pflanzenreich 415: 36. 1903. 
Plants submerged; leaves very variable in length, the petioles slender or stout, nodose- 
septate, the blades ovate to suborbicular, 4-7 cm. long, obtuse or emarginate at the apex, 
the ovate basal lobes obtuse or abruptly pointed ; scapes often shorter than the leaves, with 
few rather approximate whorls; sepals ovate, becoming 8-11 mm. long; fruit-bearing ped- 
icels short and stout, often exceeded by the bracts; fruit-heads 12-15 mm, in diameter ; 
achenes obovate, 2-2.5 mm. long, short-beaked, the margin tuberculate-crested all around, 
the faces tuberculate. 
TYPE LOCALITY: Venezuela. ; 24, 
DISTRIBUTION: Mexico and Central America; Trinidad ; also in northern South America. 
ILLUSTRATIONS: Mart. Fl. Bras. 3!: J. 15; Engler, Pilanzenreich 445: f. 12, A. 
6. SAGITTARIA IL. Sp. Pl. 993. 1753. 
Perennial, acaulescent, marsh or aquatic herbs, either more or less emersed and erect, or 
submerged and floating. Rootstock irregularly thickened or tuber-bearing. Leaves vari- 
ous, usually differentiated into petioles and blades, or represented by phyllodia. Scapes 
sometimes greatly elongate, usually simple, at least below the inflorescence. Flowers 
monoecious or dioecious, in whorls of 3 near the top of the scape, those of the lower 
whorls usually pistillate, those of the upper whorls usually staminate. Staminate flowers 
with several or many stamens; anthers 2-celled, opening by lateral slits. Pistillate flowers 
