360 FLORA. 



or clustered, erect, simple, 5-25 cm. tall. Basal leaves oblong or lanceolate, 2.5-20 

 cm. long, rather acute at the apex, cordate or subcordate at the base, long-petioled; 

 stem leaves narrowly lanceolate or linear, 2.5-7.5 cm. long, the lower petioled, the 

 upper sessile, their margins often revolute; ocreae clasping below, open above; 

 raceme solitary, terminal, narrow, rather dense, bearing a number of rather dark- 

 colored bulblets about its base; calyx 5-parted, pale rose-color or white; stamens 8, 

 exserted; style 3-parted, achene oblong, 3-angled. Greenland and Labrador to 

 Alaska, south to the high summits of the mountains of New England, and in the 

 Rocky Mountains to Colo. Also in Arctic and alpine Europe and Asia. June- 

 Aug. 



2. Polygonum amphibium L. WATER PERSICARIA. (I. F. f. 1319.) 

 Aquatic, perennial, glabrous when mature; stem floating or submersed, 1-6 m. 

 long. Leaves oblong, elliptic or elliptic-lanceolate, 4-10 cm. long, petioled, obtuse 

 or subacute at the apex, slightly inequilateral, rounded or narrowed at the base, 

 sometimes ciliate; ocreae cylindric, those of the branches often longer than the 

 internodes, their limbs sometimes spreading, usually glabrous; raceme terminal, 

 usually solitary, 12-25 mm. long, dense, erect, oblong or ovoid; calyx rose-color, 

 5-parted; stamens 5, exserted; style 2-cleft, exserted; achene orbicular-oblong, 

 lenticular, 3 mm. long, biconvex, black, smooth and shining, or granular. In 

 ponds and lakes, Quebec to Alaska, south to northern N. J., Ky., Colo, and Cal. 

 Also in Europe. July-Aug. 



3. Polygonum Hartwrightii A. Gray. HART WRIGHT'S PERSICARIA. 

 (I. F. f. 1320.) Perennial by rootstocks, more or less hispid; stem ascending, 

 decumbent or erect, 1.5-6 dm. long, many-jointed, usually rather stout. Leaves 

 lanceolate, oblong-lanceolate or oblong, 7-15 cm. long, obtuse or subacute 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, 1-2.5 cm - l n g, oblong ; calyx rose-colored, 

 5-parted; stamens 5, exserted; style exserted, 2-cleft to beyond the middle; achene 

 oblong, biconvex, lenticular, black, smooth, shining. In swamps or moist soil, 

 Hudson Bay to Ore., south to Me., S. Penn., Kans., Nev. and L. Calif. June- 

 Aug. 



4. Polygonum emersum (Michx.) Britton. SWAMP PERSICARIA. (I. F. f. 

 1321.) Perennial by long creeping or horizontal rootstocks, glabrous or strigose- 

 pubescent; stem erect or assurgent, commonly simple, enlarged at the nodes, 

 3-9 dm. or sometimes 6 m. long. 'Leaves ovate-lanceolate or oblong-lanceolate, 

 or the upper sometimes narrowly lanceolate, 6-20 cm. long, acute or usually 

 acuminate at the apex, rounded or cordate at the base, petioled, the lateral nerves 

 prominent, sometimes forking; ocreae cylindric, not ciliate; racemes I or 2, 

 erect, 2.5-8 cm. long, linear-oblong, dense; calyx dark rose-color, 5-parted; 

 stamens 5, exserted; style 2-cleft, exserted; achene broadly obovate or orbicular, 

 3 mm. long, very convex, lenticular, black and slightly granular, but shining. 

 In swamps and moist soil, Me., Ont. to N. W. Terr, and Br. Col., south to Va., 

 La. and Mex. July-Sept. 



5. Polygonum Portoricense Bertero. DENSE-FLOWERED PERSICARIA. (I. F. f. 

 1322.) Perennial, more or less scurfy; stem erect, decumbent or floating, 1-1.5 m ' 

 long or longer, branched, enlarged at the nodes. Leaves lanceolate or linear- 

 lanceolate, 4-30 cm. long, acuminate at both ends, obscurely punctate, short- 

 petioled, the nerves prominent beneath; ocreae cylindric, sometimes bristly when 

 young, naked when mature,. sometimes hispid; racemes narrow, paniculate, often 

 in pairs, 2.5-13 cm. 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, 2-3 mm. long, broadly oblong, 

 orbicular or even broader than high, black, smooth and shining, or minutely 

 granular. In wet soil, Mo. to Fla., Tex., the W. I. and S. Am. May-Nov. 



6. Polygonum incarnatum Ell. SLENDER PINK PERSICARIA. (I. F. f. 

 1323.) Annual, glabrous or nearly so ; stem erect, more or less swollen at the 

 nodes, 6-12 dm. tall. Leaves lanceolate, 7-22 cm. long, acuminate at both ends, 

 short-petioled, sparingly punctate and ciliate; ocreae cylindric, loose, brittle, 

 sometimes ciliolate when young, glabrous when mature; racemes panicled, droop- 

 ing, 3.5-10 cm. long, linear, many-flowered; calyx white or pink, small, 5-parted; 



