POLYGON ACE A E. 



3. Polygonum Hartwrightii A. Gray. 

 Hart Wright's Persicaria. (Fig. 1320.) 



Polygonum Hartzi-rightii A. Gray, Proc. Am. Acad. 

 8: 294. 1870. 



Perennial by rootstocks, more or less hispid 

 throughout; stem ascending, decumbent or erect, 

 6 / -2 long, many-jointed, grooved, usually rather 

 stout. Leaves lanceolate, oblong-lanceolate or ob- 

 long, 3'-6' long, obtuse or subacute at the apex, 

 short-petioled or sessile; ocreae cylindric, varying 

 from one-half as long to as long as the internodes, 

 the limb abruptly spreading, fringed with short 

 bristles; racemes usually solitary, dense, J^'-i' 

 long, oblong; calyx rose-colored, 5 parted; sta- 

 mens 5, exserted; style exserted, 2-cleft to be- 

 yond the middle; achene oblong, biconvex, lenti- 

 cular, black, smooth, shining. 



In swamps or moist soil, Hudson Bay to Oregon, 

 south to southern Pennsylvania, Kansas. Nevada and 

 Lower California. June-Aug. 



4. Polygonum emersum (Michx.) Britton. Swamp Persicaria. (Fig. 1321.) 



Polygonum amphibium var. emersum Michx. Fl. Bor. 



Am. i: 240. 1803. 



P. MuMenbergii'S. Wats. Proc. Am. Ac. 14: 295. 1879. 

 Polygonum emersum Britton, Trans. N. Y. Acad. Sci. 



8: 73. 1889. 



Perennial by long creeping or horizontal root- 

 stocks, glabrous or strigose-pubescent; stem erect or 

 assurgent, commonly simple, channeled, enlarged 

 at the nodes, i -3 high. Leaves ovate-lanceolate 

 or oblong-lanceolate, or the upper sometimes nar- 

 rowly lanceolate, 2^ / -S / long, acute or usually acu- 

 minate at the apex, rounded or cordate at the base, 

 petioled, the lateral nerves prominent, sometimes 

 forking; ocreae cylindric, becoming loose, not cili- 

 ate; racemes i or 2, erect, 1'-$' long, linear-oblong, 

 dense, calyx dark rose-color, 5-parted; stamens 5, 

 exserted; style 2-cleft, exserted; achene broadly 

 obovate or orbicular, \y 2 ff long, very convex, 

 lenticular, black and slightly granular, but shining. 



In swamps and moist soil, Ontario to Northwest Ter- 

 ritory and British Columbia, south to Virginia, Louisi- 

 ana and Mexico. Ascends to 3000 ft. in Virginia. 

 July-Sept. 



5. Polygonum Portoricense Bertero. Dense- flowered Persicaria. (Fig. 1322.) 



Polygonum densiflorum Meisn. in Mart. Fl. Bras. 5: 



Part i, 13. 1855. Not Blume, 1825-26. 

 Polygonum Portoricense Bertero; Meisn. in DC. Prodr. 



14: 121. 1856. 



Perennial, more or less scurfy; stem erect, decum- 

 bent or floating, 3-5 long or longer, branched, en- 

 larged at the nodes, often dark brown. Leaves lan- 

 ceolate or linear-lanceolate, i / ^ / -i2 / long, acuminate 

 at both ends, obscurely punctate, short-petioled, the 

 nerves prominent beneath; ocreae cylindric, some- 

 times bristly when young, naked when mature, some- 

 times hispid; racemes spicate, paniculate, often in 

 pairs, i '-5' long, dense, erect; calyx white or whitish, 

 5-parted to near the base; stamens 6-8, included; style 

 2-3-cleft, somewhat exserted; achene lenticular and 

 strongly biconvex or 3-angled, i"-!^" long, broadly 

 oblong, orbicular or even broader than high, black, 

 smooth and shining, or minutely granular. , 



In wet soil, Missouri to Florida, Texas, the West Indies 

 and South America. May-Nov. 



