ORDER CXXXIII. XYRIDACE^E. 543 



1. P. corda'ta, (L.) Stem none. Leaves cordate, obtuse, entire, mem- 

 branaceous, glabrous ; petioles very long, succulent. Flowers in crowd- 

 ed spikes. Corolla villous on the outer surface ; the upper lip 3-parted, 

 the lower 3-cleft, with a yellow spot at the center ; 3 of the stamens at 

 the base of the tube, and 3 at the summit. — Blue. 21. April — Sept. 

 Bogs and ditches. Wampee. 



2. P. lancifo'lia, (Muhl.) Stem none. Leaves oblong, lanceolate, 

 nearly linear when young ; in other respects similar to the preceding 

 species. 



Genus II.— HETERANTHE'RA. Beau. 3—1. 

 (From heteros, variable, and anthera, an anther.) 



Flowers in a spathe, Perianth with the border 6-parted, 

 equal. Stamens 3. Anthers unlike. Capsule 3-celled, many- 

 seeded. 



1. H. kenifor'mis, (R. <fc P.) Stem partly floating. Leaves orbicular, 

 reniform, on petioles; spathe oblong, acuminate, 3 — 5-flowered. — White. 

 U • July — Aug. Xorth Carolina. Mud Plantain. 



Genus III— SYE'XA. Pursh. 3—1. {Mayaca, Sch.) 

 (In honor of Arnold Syen, of Leyden.) 



Sepals 3, persistent. Petals 3. Stamens 3. Style 1. 

 Capsule 3-celled, 1-valved. 



1. S. fluviat'ilis, (Pursh.) Stem herbaceous, partly submersed. Leaves 

 subulate, crowded. Flowers axillary, solitary, on peduncles longer than 

 the leaves. — Purple. If. June. In w T et places. Middle Car. and Geo. 

 2 — 3 inches. Myaca Michauxii, Schw. 



Order CXXXIIL— XYRIDA'CEJE. 



Sepals glumaceous, 3. Petals 3, unguiculate. Stamens 6, 

 with 3 fertile ones inserted into the claws of the petals, and 3 

 sterile ones alternate with the petals. Ovary single. Style 3- 

 cleft. Capsule 1-celled, 3-valved, many-seeded, with parietal 

 placentas. Herbaceous plants, with radical ensiform leaves. 

 Flowers in terminal imbricate heads. 



Genus I— XY'RIS. L. 3—1. 

 (From xuros, acute, from the shape of its leaves.) 



Sepals 3, glumaceous, somewhat cartilaginous. Petals 3, 

 equal, crenate. Stigma 3-cleft. 



1. X. Elexuo'sa, (Ell.) Stem erect, spiral, dilated at the summit, 

 furrowed with two lines, glabrous. Leaves ensiform, spiral, sheathing. 

 Flowers in terminal imbricate heads. Bracts ovate, rigid, inclosing the 



r. Petal* umruiculate. Capsule l-«Selled, 8-valved* 8eed$ Dumer- 



ou-, small. — Yellow. 2{. July — Sept. Pine-barrens. Common. 2 ft. 



X. Caroliniana, Walt. 



2. X. fimbeia'ta, (Ell.) Stem erect, slightly scabrous, dilated at the 



