48 OCTANDRU. TRIGIISIA. 



160. POLYGONUil. Nuit. Gen. 370. 

 Itjrr. Polij, Eaucb, and Genu, akaee, or joint; the stem being much jointed.] 



Cal 0. Cor. 5 or 1 parted, persistent. S^eed 1, mostly 3 angled^ covered. Stam. &. .Sf^te variable. 



§ 1. Flowers axillary. 



P. Avictu..iRE. Ell- Procumbent; flowers subaessile; leaves small, lance-oblong; stipules short, lacerate- 



T''«/go— Kr.ot-^rass. 



Fl- Last of June till October. Fr. mat. September, and after- 



Jlctb- About houses, gardens, footways, &c. common. 6 to 12 inches long: flowers green and white- 



p. EPECTUM. Mahl. IMostly erect; flowers 5-androus; leaves broad-oval, rather acute. 



Si/non. p. avicuiare.w/r- latifolium. Mx. Fwig-o— Upright Knot-grass. 



Fl. lja.il of August, and after. Fr. mat. Middle of October. 



Hub. About hous:cs, yards, gardens, &c. common. 1 to 2, and 3 feet high: flowers greenish- 



Obs. I am clearly of opinion that Dr. Muhlenberg was correct, in making this a distinct species frOBJ 

 the foregoing; and have therefore followed him- 



P- TKTJUE- Ell. Stem erect, angular, fiexuose; leaves linear, strict; flowers alternate, remote. 



Siinon. P. linifolium. 3Iu!d. Bart. Fl. Phil- 



Fl. Beginning- of August, and after. Fr. mat. Beginning of October. 



Hub. Dry, sterile soils: Barrens, &c. frequent. 9 to IS inches high: flowers white, small. 



§ 2. Flowers in terminal spilies- 



P. riRGiNiAis'UJi- Ell. Spike virgate; flowers 5-androus, 2-gynous; seed rostrate; leaves lance-ovatc. 

 Fl. Last of July, and after. Fr. mat. Latter end of September. 



Hab Rich woodlands: frequent. 2 to 4 feet high: flowers white, small. 



P. PtJNCTATU.M. Ell. Spike slender, subnutant; style 3 parted; leaves lanceolate, pellucid-punctate. 

 Synon. hydropiper. Mukl. and Mx. P. hydropiperoides. Ph. Fi</go— Arse-smart. Water pepper. 

 Fl. Middle of August, and after. Fr. mat. Beginning of October. 



Hub. Barnyards, lanes, along ditches, &c. common. 12 to IS inches high; flowers green and white. 



Obs. Thisisa very hot, acrid species; and sometimes causes obstinate, painful ulcerative inflammation, 

 when applied to th« skin. 



P. MITE. Ph. Style 3 cleft; leaves narrow-lanceolate, acuminate; .stipules hirsute, long-ciliate- 

 Sijnon. p. hydropiperoides. Mx. 



Fl. Latter end of August. Fr. mat. Beginning of October. 



Hab. Moist, sterile soils: Barrens, &;c. frequent. About 2 feet high: flowers pale purple. 



p. PERsicAFiA- Ph. Flowers 6-androus, style 2 cleft; spikes oblong; leaves lanceolate; stipules ciliate- 

 Fl- IMiddle of Aupust, and after- Fr. mat. Last of September. 



Hub. Gardens, yards, roadsides, &c. frequent. 1 to 2 feet high: flowers pale rose-red- 



Obs. The leaves are genernlly marked, in the centre, with dark lunate, or heart-shaped spots- The seeds 

 of this species, though generally triquetrous, are sometimes ovate, and compressed. 



p. PENTvsYLVANicuir. Pk. Flowers crowdsd ; style2 cleft; peduncles hispid; stipules truncate. 

 Fl. Last of July, ar.d after. Fr. m.it- Beginning of October. 



Sab. Moist, low giounds: frequent- 2 to 3 feet hijih: flowers rose-red, large- 



Obs. The seeds of this species are ovate, compressed, and briefly acuminate; the flowers often 6-androUE. 

 § 3. Flowers suh-raccined: leaves sagittate, cordate, or hastate. 

 P- sAGiTTATiTit. Ell- Flowers subcapitate; style 3 cleft; stem flaccid, retrorsely aculeate; leaves sagittate- 

 Vulgo — Arrow-ieaved Tear- thumb. 



Fl. Beginning of August, and nfler- Fr. mat. Beginning of October- 



Hab. Swaniny thickets, and wet, shaded grounds: common. 2 to 4 feet long: flowers pale red. 



p. ARiFOLiUM. Eil. FIowersdistinct,G-:iudr<jua, Style 2 cleft; stem retrorsely aculeate; leaves hastate, 

 Vul^o — Halbert-leavcd Tear-thumb- 



Fl. Beginning of August, and after- 7^/- mat. ?vliddle of October. 



Hab- Swampy meadows; along rivulet«, oic common. 3 to i3 feet long: flowers pale red. s 



Ohs. The seed* are large, roundish, or ovate, and somewhat coruprcssod- I tliink ha.iiaium would have 

 been a more £>[ ri'-'i-::''!'" «l ecific m»tte- 



