440 POLYGONACE^. (BUCKWHEAT FAMILY.) 



3. P. erdctum, L. Stouter, erect or ascending {\ -2° \v\g\\), yellowish, 

 leaves oblong or oval (^-2^' long), usually obtuse; yZo^rers mostly \^" loivj, 

 often yellowisli, on more or less exserted pedicels ; stamens 5 - 6 ; achene dull, 

 included. (P. aviculare, var. erectum, Roth.) — Common, by waysides, etc. 



* * Leaves much reduced above and bract-like. 



4. P. ramosissimum, Michx. Erect or ascending (2-4° higli), yel- 

 lowish-yreen ; leaves lanceolate to linear (1-2^' long), acute ; ^o?rers and 

 achene as in n. 3, but sepals more frequently 6, the stamens 3-6, and the 

 achene mostly smooth and shining. — Sandy shores and banks of streams. E. 

 Mass. to N. Y., west to Minn., Ark., Tex., and far westward. 



5. P. tenue, Michx. Stem angled, erect (i-H° h^gh), glabrous, or 

 slightly scabrous at the nodes; leaves narrowly linear to lanceolate (1-2' 

 long), 3-nerved, acute at each end and often cuspidate, the margins somewhat 

 scabrous and at length revolute ; flowers often solitary, nearly sessile ; stamens 

 8 ; achene included, dull black. — Dry soil, N. Eng. to S. C, west to Minn., 

 Mo., and Tex. 



6. P. camporurQ, Meisn. Stein /ere/e, erect or ascending (2-3° high), 

 glabrous : leaves deciduous, linear to oblong, usually short ; pedicels slender, 

 exserted from the scarious sheaths ; stamens 8. — E. Kan. to Tex. 



§2. PERSICARIA. Flowers in dense spikes, with small scai'ious bracts; 

 leaves not jointed on the petiole ; sheaths cylindrical, truncate, entire, naked 

 or ciliate-fringed or margined ; calyx colored, ft-parted, appressed to the 

 fruit; stamens A -^', fllaments filiform ; cotyledons accumbent. 



* Sheaths and bi'acts not ciliate or fringed ; sepals not punctate ; style 2-clefl. 



7. P. lapathifdlium, L. Annual, branching, l -4° high, glabrous or 

 the peduncles often minutely glandular; leaves lanceolate, attenuate upward 

 from near the cuneate base and acuminate, somewhat scabrous with short ap- 

 pressed hairs on the midrib and margin, or rarely floccose-tomentose beneath ; 

 sheaths and bracts rarely somewhat ciliolate-, spikes oblong to linear (^-2' 

 long), dense, erect or nearly so ; flowers white or pale rose-color ; stamens 6 ; 

 achene ovate, rarely V^ broad. (P. nodosum, Peis. P. incarnatum, Man., in 

 part.) — Wet places; N. Eng. and Can. to 111., Wise, and far westward. Very 

 variable. (En.) 



Var. incarnatum, Watson. Leaves often large (6-12' long, 1-3' wide) ; 

 spikes more slender and elongated (2-4' long), nodding. (P. incarnatum, 

 £11.) — Penn. to 111., Mo., and southward. 



Var. incanum, Koch. Low (6 - 12' high) ; leaves small, obtusish, more 

 or less hoary beneath with floccose tomentum ; spikes short. — Cayuga Lake, 

 N. Y., Out., shores of L. Superior, and northwestward (En.) 



8. P. Pennsylvanicum, L. A similar species, but the branches aborr^ 

 and especially the peduncles beset with stipitate glands ; flowers larger and often 

 bright rose-color, in short erect spikes, often on exserted pedicels ; stamens 

 usually 8; achene nearly orbicular, over 1" broad. — Moist soil, in open waste 

 places, common. 



9. P. amphibium, L. Perennial, aquatic or rooting in the mud ''tout 

 and glabrous or nearly so, not branching above the rooting base; leaves usu- 

 ally floating, thick, smooth and shining above, mostly long-petioled, elliptical 



