obtuse at the apex, sometimes notched, the much-reduced upper leaves narrowly 

 oblong; inflorescence (thyrses) stiff, usually 1-2 dm. long, either all terminal on 

 leafy branches or (if leafless thyrses present) these loosely arranged and each 

 subtended by a leaf; bracts 1.5-2 mm. long, with moderately heavy excurrent 

 midrib in the male, about 2 mm. long, with heavy excurrent midrib in the female; 

 male flowers with 5 stamens and 5 tepals; inner tepals about 2.5 mm. long, obtuse 

 or emarginate; outer tepals about 3 mm. long, acuminate, with conspicuous 

 excurrent midveins; female flowers with 1 or 2 tepals, the shorter tepal rudi- 

 mentary, the longer tepal about 2 mm. long, narrowly lanceolate, acuminate, with 

 moderately heavy sometimes branched excurrent midvein; utricle about 1.5 mm. 

 long, circumscissile at the middle, thin, rugose, sometimes with faint ridges cor- 

 responding to the 3 or 4 style branches, not angled, often reddish; seed nearly 

 circular, lenticular, about 1 mm. in diameter, dark-reddish-brown. Amaranthus 

 tamariscinus Nutt. 



Sandy fields and wastelands, chiefly in moist soils, marshes, in shallow water 

 of ponds and lakes, along streams and sloughs, in swamps, alluvial soils, Okla. 

 (McCurtain, LeFIore, Ottawa, Nowata, Mayes and Alfalfa cos.), throughout most 

 of Tex. except extreme w. part, and N.M., Mar.-Oct.; Ind. to Wise, S.D. and 

 Colo., s. to N.M., Ark., Tex. and La., occasionally adv. in e. U.S. 



3. Iresine P. Br. Bloodleaf 

 About 80 species in both hemispheres. 

 1. Iresine rhizomatosa Standi. 



Perennial herb, stoloniferous with slender horizontal rhizomes; stems erect, 

 usually simple up to the inflorescence, 5-15 dm. tall, sparsely pubescent or 

 glabrous, pilose at the slightly swollen nodes, the internodes 5-14 cm. long; 

 leaves opposite, thin, bright-green, ovate to ovate-lanceolate, acute to long- 

 acuminate, entire, narrowed at the base, the larger ones 6-15 cm. long and 2-7 

 cm. broad, with a few short hairs on the upper surface along the veins, sparsely 

 pubescent beneath or glabrous; male and female flowers on separate plants; 

 staminate panicle often laxly branched, the spikelets longer; bracts and bractlets 

 ovate, silvery-white, shorter than the tepals; tepals silvery-white, ovate-lanceolate, 

 1.2-1.5 mm. long, 1 -nerved, those of the pistillate flowers subtended by long hairs 

 as a white wool; pistillate panicles 7-30 cm. long, 2.5-20 cm. broad, much- 

 branched, the branches erect or ascending, pyramidal, the spikelets opposite or 

 alternate, densely flowered, 5-20 mm. long; utricle round, 2-2.5 mm. long, equal- 

 ing or longer than the tepals; seed suborbicular, 0.5 mm. in diameter, dark-red, 

 lustrous. /. celosioides Michx., non L. 



Sandy alluvial soils, in low wet woods and thickets near streams, and wettish 

 depressions along rivers, in Okla. (Cherokee Co.), scattered in e. half of Tex., 

 w. to Denton and Comal cos., Aug.-Oct.; Md. to s. 111. and Kan., s. to e. Va., 

 Ala., La. and Tex. 



4. Altemanthera Forsk. Chaff-flower 

 About 200 species, mostly in tropical and subtropical regions. 

 1. Altemanthera philoxeroides (Mart.) Griseb. Alligator-weed. Fig. 428. 



Perennial aquatic to semiterrestrial herb; stems simple or branched, 3-10 dm. 

 long, the branches glabrous, ascending, prostrate or decumbent, stoloniferous, 

 forming mats, stout, the ascending portion 1-6 dm. long, often rooting at the 

 nodes; leaves opposite, thick and fleshy, glabrous, linear to linear-lanceolate or 

 obovate, 2-11 cm. long, 5-20 mm. broad, usually acute or mucronulate at the 

 apex, entire, narrowed to the sessile base; spikes simple, axillary or terminal, 



866 



