312 PONTEDERIACE^. Pontederia. 



in the axis of dense mealy albumen. — Marsh or water plants, with a creeping 

 rhizoma. Leaves sheathing at the base, usually on long petioles, rarely linear 

 and sessile. Flowers in spikes or racemes, sometimes axillary and solitary. 



1. PONTEDERIA. Linn.; Kuntli, emwi. 4. p. 123. PiCKERElj-WEED. 



[In honor of Jclics Pontedera, Professor of Botany at Padua.] 

 Unisema, Raf. 

 Perianth funnel-form ; the tube curved, with 3 slits on the inner curve : limb 6-cleft, 2-lipped. 

 Stamens 6 ; the 3 lower opposite the 3 segments of the lower lip, and somewhat exserted ; 

 the 3 upper much shorter, inserted lower down opposite the segments of the upper lip : 

 anthers oblong. Ovary 3-celled ; 2 of the cells empty ; the fertile cell with a single sus- 

 pended ovule. Stigma of 6 small erect acute lobes. Utricle one-seeded. — Marsh plants, 

 with flowering stems springing from a perpendicular rhizoma. Radical leaves on long 

 petioles, mostly cordate. Flowers in dense spikes, blue. 



1. Pontederia cordata, Linn. (Plate CXXXI.) Common Pickerel-weed. 



Leaves oblong-cordate; spike cylindrical, dense. — Linn. sp. 1. p. 288; Mich. ft. 1. 

 p. 194; Bot. mag. t. 1156; Red. Lil. t.72; Pursh, fl. 1. p. 223; Ell. sk. 1. p. 382; 

 Rasp. ann. du mus. 14. t.9.f.\-Q; Mirb. I. c. 16. t. 16 ; Bigel. fl. Bost. p. 130 ; Torr. 

 fl. 1. p. 342; Beck, bot. p. 368; Darlingt. fl. Cost. p. 215; Kunth, enum. 4. p. 124. 



var. angusiifolia : leaves elongated-triangular, truncate and somewhat cordate at the base. 

 Torr. I. c. P. angustifolia, Pursh, I. c. ; Nutt. I. c. ; Beck, I. c. ; Kunth, I. c. P. cordata jS., 

 Red. I. c. P. mucronata, Raf. in N. York med. rep. 11. p. 352. 



Stem erect, stout, cylindrical, bearing a single leaf. Leaves 4-6 inches long and 2-3 

 inches wide (in the var. much narrower), usually obtuse, sagittate-cordate at the base, very 

 smooth, and somewhat fleshy : petiole 3-6 inches long, the lower part dilated and sheatiiing. 

 Spathe (or rather naked sheath of the upper leaf) surrounding the peduncle. Spike 2-3 

 inches long. Flowers crowded, somewhat fasciculate, glandularly pubescent. Perianth 

 bright blue ; the tube with 3 longitudinal gashes on the lower side : upper lip flat, 3-cleft : 

 segments oblong ; the middle one broader, and usually marked with a yellow spot : lower lip 

 deeply divided into 3 linear-oblong segments. Stamens 6 : filaments slender : anthers blue. 

 Ovary oblong, tapering into a slender style, which is shorter than the longer stamens : stigma 

 minute, G-toothed. Fruit an utricle, enclosed in the persistent tube of the perianth, which is 

 at length thick, and furnished with G crested ridges. Seed smooth, oblong, acute. Embryo 

 cylindrical, in the axis of farinaceous albumen. 



Borders of ponds and rivers : common. Fl. July - August. Fr. September. The var. 

 angustifolia in Peach Pond, North Salem, Westchester county {Dr. Mead). Mountain lakes, 

 Pursh, Nuttall. 



