AMAKANTHACEAE 393 



15. Amaranthus pumilus Raf. Foliage glabrous, fleshy, deep green. Stems 

 branched at the base, the branches spreading or prostrate, 5-20 cm. long, usually abbrevi- 

 ated : leaf -blades suborbicular, rhombic or ovate, 1-1.5 cm. long, rounded or notched at 

 the apex, cuneate or truncate at the base ; petioles shorter than the blades : clusters few- 

 flowered : bracts lanceolate or oblong : sepals surpassing the bracts, oblong, obtuse : utri- 

 cle oblong, nearly twice as long as the sepals, indehiscent : seeds fully 2 mm. long. 



On sea beaches, Rhode Island to South Carolina. 



3. ACNIDA L. 



Annual coarse herbs, with branching stems. Foliage usually glabrous. Leaves al- 

 ternate : blades narrow, entire, pinnately nerved, petioled. Flowers dioecious, subtended 

 by 1-3 bracts, in terminal or axillary, narrow continuous or interrupted spikes or short 

 clusters. Staminate flowers with 5 scarious mucronate sepals surpassing the bracts and 

 5 stamens, the filaments distinct, subulate. Anthers 2-celled. Pistillate flowers destitute of 

 a perianth, with a 1 -celled ovary. Stigmas 2-5, variable in length, papillose or plumose. 

 Ovule solitary. Utricle either membranous and circumscissile or opening irregularly, or 

 fleshy and indehiscent. Seed erect, smooth and shining. WATER-HEMP. 



Utricle angled : species of the Atlantic coast region. 

 Utricle fleshy, becoming black at maturity. 



Spikes leafy to the ends : utricles over 2 mm. long. 1. A. cannabina. 



Spikes naked above : utricles less than 2 mm. long. 2. A. australis. 



Utricle membranous, green at maturity. 3. A. Floridana. 



Utricle not angled : species of the interior. 



Utricle circumscissile. 4. A. tamariacina. 



Utricle indehiscent. 



Flowers in elongated continuous or slightly interrupted spikes. 5. A. tuberculata. 



Flowers in more or less remote subglobose clusters. 6. A. concatenates. 



1. Acnida cannabina L. Somewhat succulent. Stems erect, 3-30 dm. tall, usually 

 much branched, the branches ascending : leaf -blades lanceolate, acuminate at both ends, 

 but usually blunt at the apex, entire or slightly undulate, gradually narrowed at the base ; 

 petioles shorter than the blades : flowers dioecious, the staminate in dense spikes 2-15 cm. 

 long : sepals oblong-lanceolate to ovate-oblong : utricles obovoid or subglobose, 3-5-angled, 

 2-4 mm. long, fleshy, black at maturity. 



In salt and brackish marshes, ascending rivers to fresh water, Massachusetts to Florida. Summer. 



2. Acnida australis A. Gray. Somewhat fleshy. Stems erect, 1.5-7 m. tall, widely 

 branching above : leaf-blades lanceolate to elliptic-lanceolate, 1-3 dm. long, attenuate to 

 the slender apex, undulate, cuneate or somewhat acuminate at the base ; petioles shorter 

 than the blades: flowers dioecious, the staminate in slender spikes : spikes leafy-bracted 

 at the base : utricles fleshy, ovoid, 1-1.5 mm. long, 3-angled. 



In salt or brackish marshes, Florida to Mexico, and in the West Indies. Summer and fall. 



3. Acnida Floridana S. Wats. Glabrous. Stems erect or reclining, 5-14 dm. tall, 

 simple and wand-like or sparingly branched, ridged in age : leaf-blades linear to narrowly 

 lanceolate, 5-10 cm. long, often rather blunt, remote or at least not numerous : spikes simple 

 or nearly so, conspicuously elongated, interrupted : sepals surpassing the bracts, 1-2 mm. 

 long : utricles membranous, angled, tuberculate, green at maturity. 



In sandy soil, Florida. Fall. 



4. Acnida tamariscina (Nutt.) Wood. Glabrous or nearly so. Sterna erect or 

 ascending, 1-2 m. long, much branched : leaf-blades lanceolate or ovate-lanceolate, obtuse 

 or notched at the apex, uneven along the edge, narrowed into slender petioles : spikes 

 slender, interrupted near their bases, naked or with a few leaves at the base : bracts lanceo- 

 late, firmly tipped : sepals lanceolate, 1-nerved, subulate-tipped : utricles membranous, 

 not angled, circumscissile. 



In swamps, Illinois to South Dakota, Louisiana and New Mexico. Summer and fall. 



5. Acnida tuberculata Moq. Glabrous. Stems erect, 5-30 dm. tall, usually much 

 branched : leaf-blades lanceolate to elliptic or ovate, 5-30 cm. long, obtuse or acutish, 

 prominently nerved beneath : spikes in loose or finally dense panicles : bracts often 



preading : sepals acute or acuminate : utricles ovoid, indehiscent, tuberculate, not angled. 

 In swamps or sandy bottoms, Vermont to Manitoba, Louisiana and Nebraska. Summer and fall. 



6. Acnida concatenata Moq. Glabrous or nearly so. Stems weak, often decum- 

 bent, 2-12 dm. long, with rather short internodes : leaves 1.5-15 cm. long ; blades oblong 

 to oblong-ovate, often apiculate, undulate, narrowed into slender petioles : flowers in dense 

 clusters, varying from 1-2 cm. in diameter, remote, or contiguous only toward the ends of 



