150 



POLYGON ACE^E. 



Polygonum. 



10. Polygonum Pennsylvanicum, Linn. Hairy-stalked Persicaria. 



Stem erect ; leaves lanceolate ; ochreas not ciliate ; spikes oblong, crowded, on glandularly- 

 hispid peduncles ; flowers mostly octandrous ; styles 2 ; achenium lenticular, acuminate, 

 polished. — Linn. sp. 1. p. 361 ; Michx. fl. 1. p. 240 ; Pursh, fl. 1. p. 271 ; Ell. sk. 1. 

 p. 457 ; Torr. fl. 1. p. 404 ; Meisn. I. c. p. 69 ; Beck, hot. p. 302 ; Darlingt. fl. Cest. 

 p. 250. 



Annual. Stem 2-4 feet high, paniculately branched, with tumid joints, smooth (except 

 the upper part of the branches). Leaves 3-6 inches long and 1 - 1 J inch wide, acute ; the 

 under surface, the margins and veins of the upper surface rough with short appressed hairs, 

 abruptly narrowed at the base into a petiole. Ochreas closely embracing the stem, scarious. 

 Spikes usually numerous, 1-2 inches long, erect or somewhat nodding ; the peduncles 

 clothed with short glandular hairs. Flowers rose-color, often pale, larger than in the preceding 

 species. Stamens sometimes 6. Styles united more than half their length ; the free portions 

 spreading : stigmas capitate. Achenium black and shining. 



Low moist places, banks of ditches, and cultivated grounds ; common. July - October. 

 Resembles P. Persicaria, but is easily distinguished by its hispid peduncles. 



1L Polygonum mite, Pers. Bearded Persicaria. 



Stem erect or ascending ; leaves lanceolate, hairy on the margin ; spikes slender or loose, 

 usually several together ; ochreas hairy, fringed with hairs which are nearly as long as the 

 tube ; flowers usually octandrous ; styles 3 ; nut triquetrous. — Pers. syn. 1. p. 440; Pursh, 

 fl. 1. p. 270 ; Ell. sk. I. p. 456 ; Torr.fi. I. p. 402 ; Meisn. I. c.p. 75 ; Beck, hot. p. 301 ; 

 Darlingt. fl. Cest. p 249. P. hydropiperoides, Michx. fl. I. p. 239 ; Bigel.fi. Bost. p. 156, 

 not of Pursh. 



Perennial. Stem 2-3 feet high, branching, sometimes decumbent and rooting at the joints, 

 slender, smooth. Leaves 3-4 inches long and 4-8 lines wide, narrowed at the base into a 

 short petiole ; the midrib on both sides, the margin, and often the upper surface clothed with 

 short appressed hairs ; the under surface rough with minute dots, but not pellucid-punctate. 

 Ochreas fringed with long straight brownish hairs. Spikes sometimes short and rather close, 

 at other times elongated and slender : flowers 4-5 from each ciliate bract, as large as in P. 

 Persicaria. Calyx rose-color or nearly white, not dotted. Stamens sometimes 7. Styles 

 united below : stigmas capitate. Achenium depressed, with a short acumination, black and 

 shining. 



Swamps, margins of streams, and ponds ; frequent. August - September. 



12. Polygonum Hydropiper, Linn. Water Pepper. S?nart-weed. 



Stem branched ; leaves lanceolate, marked with pellucid dots, waved ; ochreas ciliate ; 

 spikes terminal and axillary, slender, interrupted, nodding ; calyx dotted with glands ; stamens 



