554 



POLYGONACEAE. 



2. Fagopyrum Tataricum (L.) Gaertn. 

 Tartary Buckwheat. (Fig. 1317.) 



Polygonum Tataricum L. Sp. PI. 364. 1753. 

 Fagopvrnm Tataricum Gaertn. Fr. & Sem. 2: 182. 

 pi. 189. f. 6. 1791. 



Annual, similar to the preceding species, but 

 the leaves deltoid-hastate or oblong-hastate, 

 often broader than long, i r -tf wide, acute or 

 short-acuminate at the apex; racemes terminal 

 and axillary, mostly solitary, simple and few- 

 flowered, long-peduncled; flowers whitish, short- 

 pedicelled; achene subacute, lYz" long, its 

 angles crested with 3 prominent lobes above 

 the middle, its faces pinnately sulcate from a 

 conspicuous groove. 



In waste places, eastern Canada and New Eng. 

 land. Adventive from Asia. Summer. 



6. POLYGONUM L. Sp. PI. 359. 1753. 



Annual or perennial, terrestrial or aquatic herbs, some species woody, with erect, pros- 

 trate, climbing or floating stems, alternate sessile or petioled entire leaves, continuous with, 

 or jointed, to the cylindric funnelform or two-lobed, often lacerate or fringed ocreae. Flowers 

 small, normally perfect, green, white, pink or purple, variously clustered, the clusters termi- 

 nal or axillary. Pedicels jointed, subtended by ocreae or ocreolae; calyx 4~5-parted or 4-5- 

 cleft, the outer sepals or segments somewhat larger than the inner; stamens 5-9, included or 

 exserted; filaments filiform, or dilated at the base, glabrous; anthers oblong; style 2-3-parted 

 or 2-3-cleft, its branches included or exserted; stigmas capitate; achene lenticular or 3-angled 

 (rarely 4-angled), invested by or exceeding the calyx. Embryo near the end of the seed, in 

 one of its angles. [Greek, many-knees, from the swollen joints of some species.] 



About 200 species, of wide geographic distribution. Besides the following, some 33 others 

 occur in the western and southern parts of North America. 



1. Flowers in terminal spicate racemes; calyx s-cleft or 5-parted ; stem not twining. 



i. P. vii'iparum. 



Raceme solitary; alpine species; perennial, not aquatic. 

 Racemes solitary or 2; aquatic or swamp species; perennials. 

 Leaves oblong, elliptic, or elliptic-lanceolate, not acuminate. 

 Leaves narrowly lanceolate, or oblong-lanceolate, not acuminate. 

 Leaves ovate-lanceolate, or oblong-lanceolate, usually acuminate. 

 Racemes several or numerous; annuals or perennials, mostly terrestrial. 

 Ocreae naked or ciliolate, their limbs not spreading. 

 Racemes drooping. 



Achene ovoid; style 2-parted to near the base. 



Achene broadly oblong-ovoid; style 2-cleft to below the middle. 7. P. lapathifolium. 

 Racemes erect. 



Style-branches scarcely or slightly exserted. ' 



Achene broadly oblong, biconvex. 5. P. Portoricense. 



Achene orbicular, flat. 8. P. Pennsylvanicum. 



Style branches long-exserted; achene ovoid, somewhat gibbous. 9. P. longistylum. 

 Ocreae fringed with bristles, their limbs not spreading. 



Racemes not interrupted, erect; achene .lenticular or 3-angled. 

 Ocreae conspicuously fringed; achene broadly ovoid. 

 Ocreae inconspicuously fringed; achene narrowly ovoid. 

 Racemes not interrupted, erect ; achene always 3-angled. 

 Ocreolae conspicuously fringed. 

 Ocreolae inconspicuously fringed. 



Leaves mostly glabrous above; achene pointed at the top. 15. P. hydropiperoid.es. 

 Leaves strigose above; achene pointed at both ends. 13. P. setaceinn. 



Racemes not interrupted, drooping. 12. P. Carey i. 



Racemes interrupted, erect or drooping. 



Achene granular and dull; racemes drooping. 16. P. Hydropiper. 



Achene smooth, shining; racemes erect. 17. P. punctatum. 



Ocreae fringed with bristles, their limbs normally spreading. 18. P. orienlale. 



2. Flowers in long naked much interrupted spicate racemes; calyx 4-parted. 19. P. 1 'irginianMm . 



3. Flowers in axillary clusters; stems more or less wiry, not twining. 

 Plants prostrate; achene invested by the calyx. 



Achene pointed at the apex, rounded at the base. 



Leaves mostly acute; style 3-parted to below the middle. 20. P. ariculare. 



Leaves mostly obtuse; style 3-parted to the base. 21. P. littorale. 



Achene pointed at both ends. , 22. P. Bellardi. . 



Plants prostrate; achene protruding beyond the calyx. 



Leaves mostly longer than the internodes; sea beach species. 23. P. marilimum. 



Leaves shorter than the internodes; plant of waste places. 24. P. Rayi. 



2. P. amphibium. 



3. P. Harturighiii. 



4. P. emersum. ' 



6. P. incarnatum. 



10. P. Persicaria. 



11. P. persicarioides. 



14. P. Opelousanum. 



