POLYGONACEAE. 



27. Polygonum ramosissimum Michx. 

 Bushy Knotweed. (Fig. 1344.) 



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



Annual, bright green or yellowish green, gla- 

 brous, stem erect or ascending, usually very much 

 branched, slender, striate, usually rigid, 4/-4 tall. 

 Leaves lanceolate or linear- oblong, short-petioled, 

 3 // -20 // long, acuminate at both ends, persistent, 

 conspicuously jointed to the ocreae; ocreae oblique, 

 funnelform, few-nerved, becoming deeply lacerate; 

 flowers several together in the axillary clusters, 

 short-pedicelled; calyx 5-6-parted, greenish-white; 

 stamens 6 or fewer; style very short, 3-parted to the 

 base; achene 3-angled, acute, sometimes slightly 

 protruding beyond the calyx, nearly i_j" long, 

 black, reticulated, dull. 



In saline soil. Minnesota to the Northwest Territory, 

 New Mexico and California, and on the Atlantic coast 

 from Maine to New Jersey. July-Sept. 



Polygonum ramosissimum prolificum Small, Bull. Torr. Club, 21: 171. 1894, 

 Bushy, much branched, stem nearly erect, its internodes short, its nodes giving off 2 or more 

 branches; leaves narrower; flowers and achenes more numerous. Nebraska and Kansas; also on 

 the coast of Maine. 



28. Polygonum camporum Meisn. 

 Prairie Knotweed. (Fig. 1345.) 



P. camporum Meisn. in Mart. Fl. Bras. 5: 21. 1855. 

 Annual or perennial, glabrous, stem mostly 

 erect, slightly striate, much branched, some- 

 times slightly glaucous, 2-3 tall. Leaves 

 linear-lanceolate or oblong, soon falling away, 

 subsessile, rather obtuse at the apex, veined be- 

 neath, 3 // -i2 // long; ocreae funnelform, early 

 lacerate and fugacious, dark brown; flowers sev- 

 eral together in the axillary clusters, slender-ped- 

 icelled; pedicels short; stamens 8; style short, 

 3-parted; achene pyramidal-ovoid, 3-angled, 

 black, nearly i% /r long, smooth, shining. 



On prairies, Nebraska to Louisiana and New 

 Mexico. Also in South America. July-Sept. 



29. Polygonum tenue Michx. Slender 

 Knotweed. (Fig. 1346.) 



Polygonum tenue Michx. Fl. Bor. Am. i: 238. 1803. 



Annual, glabrous, somewhat rough about the 

 nodes, stem very slender or filiform, erect, simple 

 or branched, somewhat 4-angled, 4 / -i2 / tall. 

 Leaves linear or linear-lanceolate, sessile, acumi- 

 nate at the apex, 2 // -i2 // long, articulated to the 

 ocreae, i-ribbed with a lateral impression on each 

 side of the rib, the margins minutely scabrous or 

 serrulate; ocreae funnelform, soon lacerate; flowers 

 several in the axillary clusters, green, subsessile; 

 calyx-lobes whitish ; stamens 8; style 3-parted uearly 

 to the base, its branches diverging; fruit erect; 

 achene 3-angled, black, \"-\y z " long, reticulated 

 on the angles, the centre of its faces smooth. 



Dry soil, Ontario to Minnesota. Georgia and Arkan- 

 sas. Ascends to 3000 ft. in North Carolina. July-Sept. 



