Genus 5. 



BUCKWHEAT FAMILY. 



663 



9. Polygonum atlanticum (Robinson) Bick- 

 nell. Atlantic Coast Knotweed. Fig. 1623. 



Polygonum ramosissimum atlanticum Robinson, Rhodora i. • 

 72. 1902. n ' 



P. atlanticum Bicknell, Bull. Torr. Club 36 : 450. 1909. 



Annual, glabrous, bright-green, stem erect, i°-3° 

 tall, terete, but striate. Leaves narrowly elliptic or 

 linear-elliptic, or broadest above or below the middle, 

 slender-petioled, io"-2s" long, acute or slightly acumi- 

 nate at both ends; ocreae brown, early much-lacerate; 

 calyx long-pedicelled, the sepals 5 or rarely 6, with 

 pink margins; stamens mostly 5; achene ovoid or 

 rhombic-ovoid, about ii" long, 3-angled, smooth and 

 shining. 



In salt marshes and low brackish grounds, Maine to Rhode 

 Island. Aug.-Sept. 



Polygonum Bellardi All., admitted into our first edition 

 appears in our range only as a waif from the Old World. ' 



10. Polygonum erectum L. Erect 

 Knotweed. Fig. 1624. 

 Polygonum erectum L. Sp. PI. 363. 1753. 



Annual, glabrous, yellowish-green, stem erect or 

 ascending, 8-2° high, terete, nearly simple or much 

 branched. Leaves oval, oblong or obovate, subses- 

 sile or short-petioled, 3"-i8" long, obtuse or sub- 

 acute at the apex, conspicuously jointed to the 

 ocreae; ocreae oblique, soon lacerate, silvery when 

 young; flowers 1-2 together in the axils; sepals 

 greenish-yellow or yellowish, enlarged in fruit; 

 stamens 6 (sometimes 5) ; achene ovoid-pyramidal, 

 3-angled, i"-ii" long, dull, invested by the calyx, 

 or the apex slightly protruding. 



In moist or dry soil, Ontario to the Northwest Terri- 

 tory, Tennessee and Arkansas. July-Sept. 



11. Polygonum ramosissimum Michx. 

 Bushy Knotweed. Fig. 1625. 



P. ramosissimum Michx. Fl. Bor. Am. 1 : 237. 1803. 



Annual, yellowish or yellowish-green, glabrous, 

 stem erect or ascending, usually very much branched, 

 slender, striate, usually rigid, 4'-4° tall. Leaves 

 lanceolate or linear-oblong, short-petioled, 3"-2o" 

 long, acute or acuminate at both ends; ocreae few- 

 nerved, becoming deeply lacerate; flowers several 

 together in the axillary clusters, short-pedicelled ; 

 sepals S or 6, yellow or yellowish, i"-il" long; 

 stamens 6 or fewer; achene 3-angled, acute, some- 

 times slightly protruding beyond the calyx, nearly 

 li"-2" long, black. 



In saline soil, Minnesota to the Northwest Territory, 

 New Mexico and California. July-Sept. 



Polygonum camporum Meisn., admitted into our first 

 edition, is here omitted as not certainly known within 

 our area. 



