PONTEDERIACEAE. 243 



perianth-tube, 3 of them opposite the lower lip, the others opposite the upper lip ; 

 anthers oblong, subversatile, introrse. Ovary 3-celled, 2 of the cells abortive and 

 empty. Fruit enclosed in the thickened tuberculate-ribbed base of the perianth. 

 [In honor of Giulio Pontedera, 1688-1757, professor of botany in Padua.] Seven 

 or eight species, natives of America. 



i. Pontederia cordata L. PICKEREL-WEED. (I. F. f. 915.) Stem rather 

 stout, 0.3-1.1 m. tall. Leaves ovate, cordate-sagittate, 1-2 dm. long, 5-15 cm. 

 wide at the base, the apex and basal lobes obtuse ; basal lobes often with long 

 narrow appendages on the sheathing petiole ; spadix and inflorescence glandular- 

 pubescent ; perianth about 8 mm. long, it and the filaments, anthers, and style 

 bright blue, its tube curved, slightly longer than the lobes; middle lobe of the upper 

 lip with 2 yellow spots at the base within ; ovary oblong, tapering into the style ; 

 stigma minutely 3-6 toothed. Borders of ponds and streams, N. S. to Minn., 

 Fla. and Tex. The flowers are trimorphous. June -Oct. 



Pontederia cordata lancifdlia (Muhl.) Morong. Leaves lanceolate, rounded or 

 narrowed at the base, 5-25 cm. long, 6-16 mm. wide. Ont. to N. J., Cuba and Tex. 



2. HETERANTHERA R.& P. 



Herbs with creeping, ascending or floating stems, the leaves petioled. with 

 cordate, ovate, oval or reniform blades, or grass-like. Spathes I -flowered or 

 several-flowered. Flowers small, white, ^blue or yellow. Lobes of the perianth 

 nearly or quite equal, linear. Stamens 3, equal or unequal, inserted on the throat 

 of the perianth. Ovary fusiform, entirely or incompletely 3-celled by the intrusion 

 of the placentae ; ovules numerous ; stigmas 3-lobed. Fruit enclosed in the 

 withered perianth tube. Seeds ovoid, many-ribbed. [Greek, referring to the 

 unequal anthers of some species. ] About 9 species, 2 in tropical Africa, the others 

 American ; only the following in the U. S. 



Leaves mostly reniform, sometimes cordate-ovate. i. H. reniformis. 



Leaves ovate or oval, sometimes slightly cordate. 2. H. limosa. 



Leaves linear, grass-like, floating. 3. H. dubia. 



1. Heteranthera reniformis R. & P. MUD-PLANTAIN. (I. F. f. 916.) 

 Stems creeping in the mud, rooting at the nodes. Leaves cordate or reniform- 

 rarely cordate-ovate and acute, the blades 1-3 cm. long, 1.5-3.5 cm. wide; peti, 

 oles sheathing, 2-10 cm. long; spathe 2-5 -flowered; tube of the perianth slender, 

 about 8 mm. long, its lobes shorter; flowers white or pale blue; anthers basifixed, 

 the 2 upper oval, the other on a longer filament and linear. In mud or shallow 

 water, Conn, to N. J., Neb. and Kans., south to La. Also in South and Central 

 America. 



2. Heteranthera limosa (Sw.) Willd. SMALLER MUD PLANTAIN. (I. F. f. 

 917.) Stems commonly much branched from the base, 1.5-4 dm. long. Leaves 

 obtuse, roundedbr slightly cordate at the base, 2.5 cm. long or less; petioles 5-13 cm. 

 long; spathes i -flowered, often on peduncles 2 cm. long or more; flowers white or 

 blue, usually larger than those of the preceding ; filaments equal or nearly so ; anthers 

 linear, often sagittate. In mud or shallow water, Va. to Ky., Neb., Fla., La., 

 Kans. and throughout tropical America. 



3. Heteranthera dubia (Jacq.) MacM. WATER STAR-GRASS. (I. F. 918.) 

 Aquatic; stem slender, forked, often rooting at the nodes, 6-10 dm. long. Leaves 

 flat, elongated, acutish, their sheaths thin, with small acute stipule-like append- 

 ages; flowers light yellow, the perianth -segments narrow; stamens nearly equal ; 

 tube of the perianth 2-3.5 cm - l n g| spathe i-2-flowered; filaments dilated below ; 

 anthers linear, 4 mm. long, sagittate; stigma several-lolled ; capsule i -celled with 

 3 parietal placentae, many-seeded. In still water, Ont. to Ore., Fla. and Mex. 

 Also in Cuba. July-Get 



