2(1). Style 1.5-3 mm. long; leaves linear to narrowly oblong, clasping stem at 

 the auriculate base 2. A. coccinea. 



2. Style about 0.5 mm. long; leaves linear-oblong to oblanceolate, the lower 

 ones cuneate at base, the upper ones truncate to cordate-auriculate 

 at base 3. A. teres. 



1. Ammannia auriculata Willd. Fig. 542. 



Plant erect or with a few short ascending branches, to about 8 dm. high, usually 

 much smaller; leaves linear-lanceolate to linear, long-attenuate, to 5 cm. long and 

 7 mm. wide, all but the very lowest auriculate-cordate at base; cymes loosely 3- or 

 more-flowered on peduncles to 5 mm. or more long or with solitary flowers on 

 pedicels to about 3 mm. long; calyx 1.5-2 mm. long, with prominent triangular 

 teeth, 8-nerved, in fruit becoming subglobose and 2-4 mm. in diameter; petals 

 minute, purple to white, soon dropping; style filiform, 1.5-3 mm. long; capsule sur- 

 passing the calyx; seeds reddish-brown. Incl. var. arenaria (H.B.K.) Koehne. 



In swamps, ditches and about pond margins throughout much of cen. Tex., rare 

 in the Panhandle (Lipscomb Co.), Okla. (Carter, Ottawa. Comanche, LeFlore and 

 Craig cos.) and possibly Ariz., May-Sept.; from Mo. and Miss, to N.M., (?) Ariz, 

 and Mex., n. to Ind. and S.D. 



2. Ammannia coccinea Rottb. Tooth-cup. Fig. 542. 



Plants rather stout, ascending or depressed-spreading, to about 5 dm. high, the 

 stem branched below and spongy when growing in water; leaves linear-oblong to 

 linear-lanceolate, to 1 dm. long and 15 mm. wide, mosdy much smaller, cordate- 

 auriculate and clasping stem at base, acute to acuminate at apex; cymes closely 

 2- to 5-flowered, essentially sessile; calyx 2.5-5 mm. long, in fruit 3-5 mm. in 

 diameter; petals pink to purple, 1-2 mm. long, fugacious; style persistent, 1.5-3 

 mm. long; capsule about 4 mm. long. 



In mud of ditches, ponds, marshes, lakes and streams in e., cen. and extreme s. 

 Tex., Okla. (Creek, Pittsburg, Mcintosh, Stephens, Jefferson, Johnston, LeFlore. 

 Craig and Nowata cos.) and Ariz. (Maricopa, Cochise, Pima and Yuma cos.), 

 Apr.-Nov.; from Fla. to Tex. and Mex., n. to O., 111., Minn., Neb., Mont, and 

 Wash. 



Readily distinguished from A. auriculata by the compact, sessile whorls of 

 flowers and fruits. 



3. Ammannia teres Raf. Fig. 543. 



Plant erect, the stout stems simple or with few erect branches near the base, to 

 about 6 dm. high, usually much smaller, fleshy; leaves oblong to oblanceolate, 

 obtuse to subacute at apex, tapering at base or rarely subauriculate, the longer 

 leaves to 6 cm. long; flowers several in the axils, sessile; calyx teeth very short and 

 broad; petals pink, about 1 mm. long, fugacious; style thick, about 0.5 mm. long; 

 fruiting calyx about 5 mm. in diameter; seeds whitish-brown. 



Swamps and tidal marshes in s.e. Tex., summer; from Fla. to Tex., n. to N.J. 



5. Peplis L. 



A monotypic genus. 



1. Peplis diandra Nutt. Water-purslane. Fig. 539. 



Aquatic or sometimes terrestrial herb, rooting in mud, glabrous, with slender 

 simple stems to about 4 dm. long; leaves opposite, those of submersed plants elon- 

 gated, linear, minutely retuse at the obtusish apex, thin and flaccid, closely sessile 

 by a broad base, to about 3 cm. long and 3 mm. wide, when emersed shorter and 

 contracted at base; flowers small, greenish, solitary and sessile in axils of leaves; 

 calyx without appendages, 2-3 mm. long, with 4 broad triangular pinkish lobes; 



1162 



