536 PONTEDERIACE^E. (PICKEREL-WEED FAMILY.) 



1. PONTEDERIA, L. PICKEREL-WEED. 



Perianth funnel-form, 2-lipped ; the 3 upper divisions united to form the 3- 

 lobed upper lip ; the 3 lower spreading, aiid their claws, which form the lower 

 part of the curving tube, more or less separate or separable to the base ; after 

 flowering the tube is revolute-coiled from the apex downward, and its fleshy- 

 thickened persistent base encloses the fruit. Stamens 6 ; the 3 anterior long- 

 exserted ; the 3 posterior (often sterile or imperfect) with very short filaments, 

 unequally inserted lower down ; anthers versatile, oval, blue. Ovary 3-celled ; 

 two of the cells empty, the other with a single suspended ovule. Utricle 1- 

 celled, filled with the single seed. Stout herbs, growing in shallow water, 

 with thick creeping rootstocks, producing erect long-petioled mostly heart- 

 shaped leaves, and a 1-leaved stem, bearing a spike of violet-blue ephemeral 

 flowers. Root-leaves with a sheathing stipule within the petiole. (Dedicated 

 to Pontedera, Professor at Padua at the begiuning of the last century.) 



1. P. cordata, L. Leaves arrow-heart-shaped, blunt, or sometimes tri- 

 angular-elongated and tapering and scarcely cordate (var. ANGusxirdLiA, 

 Torr.) ; spike dense, from a spathe-like bract; upper lobe of perianth marked 

 with a pair of yellow spots (rarely all white) ; calyx-tube in fruit crested with 

 6 toothed rfdges. X. Scotia to Fla., west to Minn, and Tex. July -Sept. 



2. HETERANTHERA, Ruiz & Pav. MCD-PLAXTAIX. 



Perianth salver-form with a slender tube ; the limb somewhat equally 6- 

 parted, ephemeral. Stamens 3, in the throat, usually unequal ; anthers erect. 

 Capsule 1-celled or incompletely 3-celled by intrusion of the placentae, many- 

 seeded. Creeping, floating or submerged low herbs, in mud or shallow water, 

 with a 1 - few-flowered spathe bursting from the sheathing side or base of a 

 petiole. (Name from ITS'/HZ, different, and dvOrjpd, anther.) 



* Stamens unequal; 2 posterior filaments with ovate yellow anthers ; the other 



longer, with a larger oblong or sagittate greenish anther ; cajimili- incompletely 

 3-celled ; leaves rounded, long-petioled ; creeping or floating plants. 



1. H. reniformis, Ruiz & Pav. Leaves round-kidney-shaped to cordate 

 and acute ; spathe 3 - 5-flowered ; flowers white or pale blue. Conn, to N. J., 

 west to 111. and E. Kan., and southward. (S. Am.) 



2. H. limosa, Vahl. Leaves oblong or lance-oblong, obtuse at both ends ; 

 spathe 1 -flowered; flowers larger, blue. Va. to Mo. and La. (S. Am.) 



* * Stamens alike, with sagittate anthers; capsule l-celled, with 3 parietal pla- 



centce ; leaves linear, translucent, sessile ; submerged grass-like herbs, with 

 on/// the flowers reaching the surface. 



3. H. graminea, Vahl. The slender branching stems clothed with 

 leaves and bearing a terminal 1 -flowered spathe (becoming lateral) ; flowers 

 small, pale yellow, with a very long thread-like tube. (Schollera gramiuifolia, 

 Willd.) N. Eng. to N. C., west to Minn, and E. Kan. 



ORDER 118. XYRIDACEJE. (YELLOW-EYED-GRASS FAMILY.) 



Rush-like herbs, ivith equitant leaves sheathinr/ the base of a naked scape, 

 which is terminated by a head of perfect 3-androns Jlowers, with extrorse 



