CHENOPODIACEAE. 87 



Polygonum hartwrightii Gray. Perennial, on muddy banks, more or less 

 strigose-pubescent especially on the sheaths and bracts. Spokane, De- 

 wart. Some botanists consider this only a hairy terrestrial state of P. am- 

 phibium. 



Polygonum amphibium L. Perennial, aquatic, glabrous or nearly so; 

 leaves floating, elliptic or oblong, obtuse or acutish, smooth and shiny above, 

 5-12 cm. long, long-petioled; spikes dense, 2-3 cm. long. In ponds and 

 lakes. 



Polygonum emersum (Michx.) Britt. Perennial, sparsely scabrous through- 

 out; stems erect or decumbent, 1-2 m. long, rooting at the nodes; leaves 

 oblong-lanceolate, acuminate, cuneate or rounded at base, 8-16 cm. long, 

 short-petioled; sheaths cylindric, loose, entire; spikes dense, 3-7 cm. long, 

 short-peduncled; calyx rose-red, 5-parted; akenes lenticular, black, shiny, 

 slightly roughened. Common in wet meadows and on pond and river 

 banks. 



Polygonum persicaria L. Annual, erect or ascending, glabrous or pu- 

 berulent; stems 15-90 cm. long; leaves lanceolate, acute or acuminate at each 

 end, short-petioled, 525 cm. long, frequently with a brown-purple spot near 

 the middle, glabrous or sparsely puberulent below and on the midrib and 

 margins above; sheaths tubular, 10-15 mm. long, coarsely fringed; spikes 

 slender, 2-4 cm. long, slender peduncled, erect; calyx pink, 5-lobed; akene 

 lenticular, black and shining. Sparingly introduced. 



Polygonum lapathifolium L. Stems branched, 15-80 cm. high, erect or 

 ascending; leaves lanceolate, acuminate, scabrous on the midrib and margins, 

 10-20 cm. long; peduncles minutely glandular; spikes axillary and terminal, 

 slender, 2-10 cm. long, erect or nodding; flowers white or pink; stamens 6; 

 akene ovate, lenticular. Sparingly introduced or perhaps native along Snake 

 River. 



Polygonum tomentosum incanum (Schmidt) Gurke. Annual, simple or 

 branched, 10-30 cm. high; leaves lanceolate, acute, 2-6 cm. long, green above, 

 white woolly beneath; peduncles decidedly glandular; spikes shorter, 1-3 cm. 

 long. On river banks, rare. 



Family 32. CHENOPODIACEAE. GOOSEFOOT FAMILY. 



Mostly annual or perennial herbs; stems angled, striate or 

 terete; leaves alternate or sometimes opposite, simple, entire, 

 toothed or lobed, mostly petioled, without stipules; flowers per- 

 fect, polygamous, monoecious or dioecious, small, greenish, 

 regular or slightly irregular, commonly in panicled spikes, with 

 or without bracts; calyx persistent, 2-5-lobed or parted, or 

 rarely reduced to a single sepal or in some pistillate flowers 

 wanting; petals none; stamens as many as the calyx lobes or 

 fewer and opposite them; disk usually none; ovary mostly free 

 from the calyx, 1-celled; ovule 1; fruit a utricle; endosperm 

 mealy, fleshy or wanting. 



