and female flowers on separate plants; staminate flowers with 5 erect membranous 

 or scarious oblong to lanceolate 1 -nerved tepals; stamens 5, the anther locules 

 united only at the middle, the anthers linear-oblong; pistillate flowers naked, with- 

 out or with 1 or 2 tepals; ovary flattened, obovate or rotund; style very short or 

 absent; style branches 2 to 5, usually elongate, plumose-hispid; ovule 1; utricle 

 thin-walled or fleshy to somewhat coriaceous, indehiscent, irregularly bursting or 

 circumscissile, usually 3- to 5-angled; seed erect, smooth, reddish-brown or nearly 

 black, lustrous; embryo annular, the endosperm copious. 

 About half a dozen species in Western Hemisphere. 



1. Plants pistillate (2) 



1. Plants staminate (3) 



2(1). Tepals completely lacking or irregularly present and rudimentary, less than 

 1 mm. long and without visible midveins; utricle indehiscent, with 



conspicuous longitudinal ridges; leaf blade broadly lanceolate 



1. A. cuspidata. 



2. Tepals regularly present and well-developed, at least 1 mm. long and with 



distinct midveins, 1 or 2, lanceolate to linear; utricle circumscissile, 

 rugose, with faint ridges; leaf blade usually oblong to lanceolate.... 

 2. A. tamariscina. 



3(1). Outer tepals without heavy midveins and not appreciably longer than the 

 inner, with excurrent midveins; bracts mostly with slender midribs 

 not over 2 mm. long, the midrib conspicuously excurrent; leaf 

 blades usually lanceolate, more than 1 cm. wide; inflorescence 



often with several branch thyrses not subtended by leaves 



1. A. cuspidata. 



3. Outer tepals 3 mm. long, with heavy midveins, definitely longer that the inner, 



the midribs excurrent as rigid spines; bracts with heavy midribs, 

 mostly over 2 mm. long, definitely shorter than the outer tepals; 

 leaf blades usually oblong to linear-oblong 2. A. tamariscina. 



1. Acnida cuspidata Spreng. Southern water-hemp. 



Glabrous herb; stems stout, 2-3 (-9) m. tall, usually much-thickened at the base, 

 smooth, succulent, much-branched above; leaves few to numerous, with slender 

 petioles 2-20 cm. long, narrowly lanceolate to ovate, 6-30 cm. long, 5-14 mm. 

 wide, acuminate or long-attenuate at the apex, rounded to acute at the base, undu- 

 late, yellowish or bright-green, prominently veined beneath; inflorescences (thyrses) 

 flexible or moderately stiff, usually 5-10 cm. long, the terminal thyrse often 

 accompanied by leafless branch thyrses and the uppermost of these not subtended 

 by leaves, the branch thyrses somewhat more numerous and more crowded in the 

 male than in the female plants; bracts 1.5-2 mm. long, the midrib moderately 

 heavy in the male and heavy in the female, not conspicuously excurrent in either; 

 male flowers with 5 stamens; the 5 tepals approximately equal, 1.2-3 mm. long, 

 the inner emarginate, the outer acuminate with excurrent midveins; female flowers 

 without perianth; style branches 3 to 5, short and stout; utricle obovoid to turbi- 

 nate, 1.5-2.5 mm. long, fleshy, indehiscent, with 3 to 5 prominent longitudinal 

 ridges, not rugose, stramineous; seed flattened, 1-1.25 mm. in diameter, turgid, 

 round, smooth to minutely granulate, dark-reddish-brown to black, lustrous, 

 Acnida alabamensis Standi., Amaranthus australis (Gray) Sauer. 



In salt and marshy places, from coastal Tex., n.w. to the Plains Country, May- 

 Aug.; Coastal Plain from Fla. to Tex. and Yuc, W.I., Trin. and Venez. 



2. Acnida tamariscina (Nutt.) Wood. Nuttall's water-hemp. Fig. 427. 



Herb, glabrous or nearly so; stems stout, erect or ascending, simple or branched, 

 1-2 m. tall; leaves alternate, with slender petioles to 5 cm. long, rhombic-oblong 

 or lanceolate to ovate-lanceolate, to 1 dm. long, attenuate at the base, rounded or 



864 



