2. Lythrum lanceolatum Ell. 



Plant to 1 m. or more high, the stem usually much-branched (especially above), 

 often in large clumps; stem leaves elliptic to elliptic-lanceolate, to 55 mm. long and 

 1 cm. wide, acute to acuminate at apex, tapering to a cuneate base with straight 

 margins; leaves of inflorescence similar to stem leaves but much smaller; calyx tube 

 about 5 mm. long, the slenderly subulate appendages much longer than the teeth; 

 petals obovate, purple or cerise-red to lavender-blue, 3-6 mm. long; ovary with a 

 thick ring at base. L. alatiim Pursh var. lanceolatum (Ell.) T. & G. 



Rather frequent in meadows, prairies, marshes, about lakes and ponds, ditches 

 and depressions in the e. third of Tex., rare elsewhere in Tex. and Okla. (Johnston, 

 McCurtain, Haskell, Choctaw, Grady, LePlore and Love cos.), Apr.-Oct.; from 

 Tex. and Okla., e. to Fla., Va. and Tenn. 



3. Lythrum dacotanum Nieuw. 



Perennial from a woody rootstock, to about 1 m. high, the stems mostly much- 

 branched, rarely simple; stem leaves elliptic to elliptic-lanceolate or linear- 

 lanceolate, rounded to subauriculate at base, obtuse to acute at apex, to 35 mm. 

 long and 7 mm. wide; leaves of inflorescence similar to the stem leaves but much 

 smaller; calyx tube 5-6 mm. long; petals purple, obovate, 5-7 mm. long. L. alatum 

 of Okla. and Tex. reports (probably). 



Mostly in prairies and meadows, seepage areas and about ponds and lakes, of 

 Panhandle and n.-cen. Tex. and Okla. (Jeff'erson and Mayes cos.), May-July; from 

 Tex. and Ark., e. to Ga., Tenn. and Va., w. to Colo, and Wyo., n. to Ont. 



4. Lythrum califomicum T. & G. Hierba del cancer. Fig. 541. 



Perennial with creeping woody rootstock, to 15 dm. high, usually much smaller, 

 pale-green and glabrous; stems mostly erect, paniculately and divaricately branched 

 above; stem leaves alternate, firm, narrowly linear to linear-oblong or the lower 

 leaves sometimes lanceolate, acute at apex, more or less rounded to somewhat 

 auriculate at the sessile base, to about 3 cm. long and 5 mm. wide; leaves of inflor- 

 escence linear, obtuse to acute, much smaller than the stem leaves; calyx tube 

 cylindric, 5-7 mm. long, the subulate teeth sharply acute; petals obovate, bright- 

 purple, 4-6 mm. long, 2-4.5 mm. wide; capsule oblong-clavate, the linear- 

 lanceolate seeds about 1 mm. long. L. alatum Pursh var. beviflomm (Gray) Wats., 

 L. Unearifolium (Gray) Small, L. parvulum Nieuw. 



In moist ground or water along streams, marshes, about ponds and springs, in 

 depressions, and salt flats mainly in s.-cen. and w. Tex., Okla. (probably), N. M. 

 (Grant, Sierra, Don Ana, Socorro, Otero and Chaves cos.) and Ariz, (widespread), 

 Mar.-Nov.; from Tex., n. to Kan. and w. to Calif, and n. Mex. 



4. Ammannia L. 



Mostly low and inconspicuous glabrous annual herbs, the stems mostly 4-angled: 

 leaves opposite, sessile, entire, narrow and often elongated; flowers small, usually in 

 3- to many-flowered axillary cymes, usually 4-merous; calyx globose or campanu- 

 late. 4-angled, 4-toothed, usually with a little horn-shaped appendage in each sinus; 

 petals 4, small, deciduous, sometimes wanting; stamens 4 to 8. inserted on the calyx 

 tube; style somewhat persistent; capsule 2- to 4-celled, bursting irregularly; seeds 

 numerous, angled and minutely pitted. 



About 30 species widespread in tropical and warm temperate regions. 



1. Cymes decidedly pedunculate; mature capsule surpassing the calyx 



\. A. auriculata. 



1. Cymes sessile or essentially so; mature capsule equal to or shorter than the 

 calyx (2) 



1161 



