POLVGOOTM POLYGONACE^ 579 



ovate apicate raceme : calyx rose-color, about 2 lines long, 6-parted to below 

 the miadle: stamens 5, asserted: st;^le about 2 lines long 2-cleft: acheneH 

 lenticular, orbicular-oblong or obovoid. In ponds and wet places, Alaska 

 to California and the Atlantic States : also Europe and Asia. 



P. Hartwri^htii Gray Proc. Am. Acad viii, 294 Perennial : more or 

 less hispid throuitbout, except when growing in^water : stems creeping and 

 ascending, or snberect, 1-3 feet long, leafy: leaves oblong to narrowly lan- 

 ceolate, 3-9 inches long, obtuse or acuiish at both ends, short-petioled or 

 sessile: ocreae cylindric, 6-9 lines long, with a more or less spreading rim, 

 fringed at the summit with short bristles : flowers numerous, in a dense 

 oblong to conic spicate raceme : calyx rose-color, about 2 lines long, 6-parted 

 to below the middle : stamens 5, exserted : ach^nes lenticular, oblong. In 

 moist places, Alaska to California and the Atlahtic States. 



P Mahlenbergii Watson Proc. Am. Acad, xiv, 245. Perennial : glab- 

 rous or strigose throughout : stems more or less creeping in wet places, the 

 distal end erect, 12-30 inches long, mostly siniple, leafy, enlarged at the 

 joints : leaves narrowly to broadly lanceolate,.- 2-10 inches long, acute or 

 acuminate, rounded or narrowed to cordt|ite at base, all petioled : ocreae 

 cylindric, 12-18 lines long, wheri young clasping the stem, becoming loose 

 and inflated near the base in age : flowers in 1-3 terminal linear densely- 

 flovirered racemes 2-5 inches long : calyx dirk rose-color to pink, 2 lines long, 

 5-parted tp the middle : stamens 5, exserted: style 2-cleft, exserted : achenes 

 lenticular, broadly obovoid. In water or wet places, throughout North 

 America. 



P. LAPATHiFOLiuM L. Sp. 360. Aonual ; glabrous or more or less pu- 

 bescent throughout: stem stout, mostly erect, 1-2 feet high, branched 

 above or throughout, sometimes nearly simple, thickened at the joints: 

 leaves broadly to narrowly lanceolate, 2-10 inches long, attenuate totrard 

 the apex from the broadest part, acuminate at base, ciliate, inconspicuous- 

 ly punctate, short-petioled : ocreae cylindric, 6-12 lines long, loose, striate 

 or ribbed, slightly ciliate when young : peduncles and pedicels more or less 

 glandular: racemes 1-5, in a terminal panible, denselv flowered, 1—1 inches 

 long, mostly drooping : calyx flesh-color to white, 5-parted to below the 

 middle: stamens 6, included: achenes lehticular Qr trigonous, oblong or 

 ovoid. In moist places, throughout temperate North America : introduced 

 from Eurppe. 



Tar. incaunm Koch Syn. Fl. Germ. 711. Small and slender : stem 

 erect, 2-12 inches high, simple or branched: leaves lanceolate to ovate or 

 pblong, glabrous above, white- tqmentose beneath, short-petioled or sub- 

 sessile: racemes oblong, 6-12 line|~]long, erect: achenes lenticular, ovoid. 

 In damp places, Oregon and Washington to the Atlantic States. 



P. nodosnm Persoon Syn. i, 440. Annual; stem-stout, erect, 1-4 feet 

 high, red or reddish with purple spots and dai'k ring^, naked, branched: 

 leaves rather narrowly lanceolate, attenuate upward from near the base 

 and acuminate, cuneate at base and Shortly petioled, somewnat scabrous 

 with short prickly hairs on the midribs and uiargins: ocreae cylindric, 

 8-12 lines long, strongly ribbed: racemes axillary and terminal, oblong 

 and erect or often linear and nodding, an inch long or more : flowers white 

 to light rose-color, about a line long: stamens 6, included: style 2-parted, 

 included : achenes lenticular, broadly oblong or ovoid. Throughout North 

 America. 



P. Pennsylvanicam L. Sp. 362. Annual: glabrous below, pubescent 

 and glandular above: stem erect, 1-3 feet high, simple to much branched : 

 leaves from narrowly to broadly lanceolate, 2-10 inches long, ciliate, the 

 midrib prominent on the lower side, acuminate at base, short-petioled : 

 ocreae cylindric or funnelform, 6-9 lines long: racemes panicled, oblong- 

 cylindric, 1-3- inches long, erect, dense; calyx pink or light purple, 1-2 



