676 



POLYGONACEAE. 



Vol. I. 



1. Pleuropterus Zuccarinii Small. Japanese Knotweed. Fig. 1655. 



Polygonum cuspidatum Sieb. & Zucc. Fl. Jap. Fam. Nat. 



2:84. 1846. Not Willd. 1825. 

 Polygonum Zuccarinii Small, Mem. Dept. Bot. Col. Coll. 



1 : 158. pi. 66. 1895. 



Perennial, glabrous, more or less scurfy, stem 

 stout, erect, woody below, terete or slightly angled, 

 much branched, 4°-8° tall. Leaves oblong-ovate or 

 ovate-lanceolate, petioled, 2'-6' long, acuminate- 

 cuspidate at the apex, truncate or subcordate at the 

 base, reticulate-veined on both surfaces, their mar- 

 gins undulate; ocreae oblique, smooth, fugacious; 

 racemes mostly terminal, panicled, 2'-4' long, or 

 axillary, many-flowered, more or less pubescent ; 

 flowers greenish-white, long-pedicelled ; outer seg- 

 ments of the S-parted calyx very broadly winged in 

 fruit; stamens 8; style 3-parted; achene 3-angled, 

 narrowly oblong or oblong-pyramidal, \\"-i\" long, 

 black, smooth, shining. 



Escaped from cultivation locally throughout our range. 

 Native of Japan. July-Oct. 



13. POLYGONELLA Michx. Fl. Bor. Am. 2 : 240. 1803. 



Annual or perennial glabrous herbs, sometimes slightly woody, with erect branched 

 usually conspicuously jointed stems, alternate narrow leaves articulated to the ocreae, and 

 small white or greenish flowers in slender panicled racemes. Calyx unequally s-parted, 

 persistent, its segments petalloid, loosely investing the achene or its base in fruit, the three 

 inner calyx-segments often winged. Stamens 8, included ; filaments filiform, or much dilated 

 or auricled at the base. Style 3-parted, short or almost wanting; stigmas capitate; ovary 

 i-celled; ovule solitary. Achene 3-angled, smooth. Embryo slender, nearly straight, in one 

 of the angles of the seed. [Diminutive of Polygonum.] 



About 8 species, natives of eastern North America. Type species : Polygonella parvifolia Michx. 



Annual ; inner sepals not winged in fruit ; pedicels reflexed. 

 Perennial ; inner sepals winged in fruit ; pedicels divergent. 



1. P. articulata. 



2. P. americana. 



i. Polygonella articulata (L.) Meisn. Coast Jointweed.' Fig. 1656. 



Polygonum articulatum L. Sp. PI. 363. 1753. 



Polygonella articulata Meisn. Gen. 2 : 228. 1836-43. 



Annual, glaucous, stem slender, wiry, erect or 

 sometimes diffusely spreading, simple or branched, 

 striate or slightly angled, 4-10' long. Leaves linear 

 or linear-subulate (apparently filiform from the 

 revolute margins), sessile, 4"-2o" long, jointed to 

 the summits of the ocreae, cylindric, slightly ex- 

 panded at the summit; racemes numerous, erect, 

 many-flowered, i'-ii' long; ocreolae crowded or 

 imbricated; pedicels reflexed; calyx-segments white 

 with a dark midrib, loosely investing the achene, not 

 winged in fruit; achene narrowly ovoid-pyramidal, 

 pointed, 1" long, brown, smooth, shining. 



In sands of the seashore and sandy soil along the 

 coast, Maine to Florida, and on the shores of the Great 

 Lakes. Sand-grass. July-Oct. 



