440 POLYGONACE^E. (BUCKWHEAT FAMILY.) 



3. P. er6ctum, L. Stouter, erect or ascending (1 -2 high), yellowish - t 

 leaTes oblong or oval (1-2^ long), usually obtuse; flowers mostly l" long, 

 often yellowish, 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 high), yel- 

 lowish-green; leaves lanceolate to linear (1-2-J' long), acute; flowers 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. t6mie, Michx. Stem angled, erect (-li high), 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. campbrum, Meisn. Stem terete, 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 scarious bracts ; 

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

 or ciliate-J ringed or margined; calyx colored, 5-parted, oppressed to the 

 fruit; stamens 4-8; filaments filiform; cotyledons accumbent. 

 * Sheaths and bracts not ciliate or fringed; sepals not punctate; style 2-cleft. 



7. P. Iapathif61ium, L. Annual, branching, 1 -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 I" broad. (P. nodosum, Pers. P. incarnatum, Man., in 

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

 variable. (Eu.) 



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

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

 Ell.) Penn. to HI., 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., Ont., shores of L. Superior, and northwestward (Eu.) 



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

 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, stout 

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

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



