polygonej;. 43 



or quite distinct sepals; the outer herbaceous, spreading or reflexed; 

 inner larger, in some becoming greatly enlarged in fruit, appressed to 

 the 3-angled achene. Stamens 6; filaments very short. Styles 3 (or 2); 

 stigmas tufted. Embryo lateral, slender, slightly curved. 



* Fl. perfect or polygamous ; valves accrescent, often with a grain-like pro- 

 tuberance on the back; leaves elongated, never hastate, pinnately 

 ■many-veined; herbage scarcely acidulous. 



+- Valves small (2 lines, more or less), one or more of them grain-bearing. 

 ++ Valves with slender awned teeth; herbage pubescent or scabrous. 



1. K. OBTUsrFOiiius, L. Tall (3 — 5 ft.), slender, somewhat scabrous : 

 radical leaves oblong, obtuse, cordate or truncate at base, long-petioled, 

 the blade 6 — 15 in. long: fl. in loose whorls, on long pedicels, these 

 jointed below the middle: valves ovate-deltoid, 2 — 3 lines long, with 1 — 3 

 setaceous teeth on each side, usually only one valve grain-bearing. — 

 Naturalized, but rather sparingly, and in low lands only. 



2. E. pulohbb, L. Erect, 2 — 3 ft. high, with rigid branches divari- 

 cately and widely spreading: leaves scabrous beneath, the radical oblong 

 or lanceolate (sometimes panduriform), acute, at base cordate or obtuse : 

 fl. on short stout rigid pedicels: valves ovale, 2 — 3 lines long, with 4 — 6' 

 rigidly awned teeth on each side. — Very abundant by way-sides. 



3. K. polygonoides, L. Low (about 1 ft.), erect, stout, from an 

 annual or biennial root: herbage minutely pubescent and of a pale or 

 yellowish green: leaves linear-lanceolate, the margin somewhat crisped 

 or undulate, short-petioled, the blade 1 — 4 in. long: inflorescence com- 

 pact, the verticils dense: valves 1 line long, ovate-lanceolate, all grain- 

 bearing, and with 8 or 8 long-awned teeth on each side. — Common in 

 brackish marshes, and on lake shores. 



++ ++ Valves entire or only denticulate; herbage glabrous. 



4. R. congijOMBratus, Murr. Stoutish, 3 — 4 ft. high, leafy-paniculate 

 above: radical leaves ovate or lanceolate, cordate, slightly undulate: 

 pedicels short, stout and geniculate in fruit, jointed near the base: valves 

 small, all grain-bearing, ovate-lanceolate, acute. — In wet places. 



5. R. oeispus, L. Size and habit of the last, but panicles less leafy 

 and more condensed: leaves long-petioled, truncate at base, strongly 

 undulate or crisped: pedicels 2 — 4 lines long, rather slender: valves all 

 grain-bearing, ovate or cordate, strongly reticulate. — In waste lands. 



6. B. Berlandieri, Meisn. Stout, erect, 2—4 ft. high: leaves nar- 

 rowly lanceolate, very undulate, more or less acuminate, narrowed below 

 to an abruptly cuneate or almost truncate base, 6 in. long, short-petioled; 



