2. Pontederia L. Pickerel-weed 



Stout herbs with thick creeping rhizomes rooted in mud; leaves erect, long- 

 petioled, with a sheathing stipule within the petiole; leaf blades variable, broad 

 or narrow; inflorescence an erect spike of violet-blue ephemeral flowers from a 

 sheathing spathe, with a solitary leaf on the flowermg stem; perianth funnelform, 

 2-lipped, the tube revolute-coiled after flowering; stamens 6, the 3 upper un- 

 equally inserted, the 3 lower long-exserted; anther elliptic, blue, versatile; ovary 

 3-celled; fruit a 1 -seeded utricle. 



About 6 species in warm regions of the Western Hemisphere. 



The seeds are sometimes eaten by ducks and muskrats. 



1. Perianth villous in bud, becoming glabrate with age, rarely sparsely glandular 

 1. P. cordata var. cordata. 



1. Perianth persistently pubescent with short glandular hairs 



1. P. cordata var. lanceolata. 



1. Pontederia cordata L. var cordata. Fig. 306. 



Stem up to 1 m. tall; leaf blades varying from deltoid-ovate to triangular- 

 lanceolate, prominently and deeply cordate to truncate or rarely narrowed at 

 base, to 2 dm. long; spike to 15 cm. long. 



In marshes, sluggish streams and ditches in shallow water of n.-cen. and e. 

 Okla. (Alfalfa, Cherokee and McCurtain cos.) and e. Tex., June-Sept.; P.E.I, 

 and N.S., s. to Fla., w. to Mo., Okla. and Tex. 



Var. lanceolata (Nutt.) Griseb. Similar to var. cordata in habit and habitat; 

 leaf blade usually somewhat firmer than in that variety. P. lanceolata Nutt. Fla. 

 w. to e. Tex. and e. Okla. (McCurtain and Payne cos.), locally n. to Del. 



3. Heteranthera R. & P. Mud-plantain 



Herbs submersed, floating or rooted in mud, forming a rosette or with elongate 

 simple or branched stems; leaves sessile or petiolate; leaf blades straplike to ovate 

 or lanceolate to reniform, leathery to thin and pellucid; flowers solitary or several 

 in a spike, from a spathe that arises from the sheathing side of a petiole or in 

 the axis of leaves; perianth salverform, the limb more or less equally 6-parted, 

 ephemeral; stamens 3. equal or unequal; anthers ovate to sagittate, basifixed; 

 capsule 1- or incompletely 3-celled by intrusion of the placentae, many-seeded. 



About a dozen species in America and Africa, mostly tropical. 



Ducks are known to eat the seeds, and the dense growth occasionally formed 

 by H. dubia provide food and shelter for fish. 



1. Leaves sessile, linear, grasslike, pellucid; spathe sessile in axils of leaves; 

 stamens all alike; anthers coiled with age (2) 



1. Leaves petiolate, with an expanded thickish blade; spathe peduncled; stamens 



dimorphic; anthers not coiled (3) 



2(1). Perianth tube much less than twice as long as the spathe; seeds ellipsoid, 



yellow-brown, the 10 to 12 membranaceous wings evanescent 



I. H . dubia. 



2. Perianth tube twice as long as the spathe or longer; seeds nearly globose, 



black-brown, the 14 to 16 wings persistent 2. H. Liebmannii. 



3(1). Spathe 1-flowered; leaf blade ovate to elliptic or elliptic-lanceolate 



3. H. limosa. 



3. Spathe 3- to 10-flowered; leaf blade round-reniform 4. H. reniformis. 



1. Heteranthera dubia (Jacq.) MacM. Water star grass. Fig. 307. 



Submersed grasslike herb, with slender branching stems often rooting at the 

 nodes; leaves linear or ribbonlike, thin, sessile, finely parallel-veined and without 



601 



