410 POLYUOXACE.E. (BUCKWHEAT FAMILY.) 



escaped from cultivation. June -Sept. Stem 3 -5 high. Spikes 2' -3' 



long. 



V. PEKSICAKIA. Flowers in closely-bracted spikes: stamens 4-8: styles 



2-3, or 2-3-uleft: achenium 3-any/ed or lenticular: cotyledons accumbent: 



albumen horny : sheaths cylindrical, truncate. 



* IS heaths naked : style 2-cle/i or 2-jiarted : achenium lenticular. 



2. P. incarnatum, Ell. Stem smooth below, the summit of the 

 branches, peduncles, and calyx sprinkled with glandular dots ; leaves lance- 

 olate, long-acuminate, petioled; spikes racemed, linear, nodding; bracts 

 longer than the pedicels ; flowers small, flesh-color ; stamens 6 ; style 2-parted ; 

 aclienium ovate, with the sides concave. Ponds, ditches, etc., South Caro- 

 lina, and westward. July - Oct. Stem 2 - 3 high. Leaves 6' - S 

 long. Spikes 1'- 2' long. 



3. P. densiflorum, Meisner. Stem stout, smooth, branching above; 

 leaves lanceolate or oblong-lanceolate, acuminate ; spikes racemed or some- 

 what pauicled, linear, erect, dense-flowered, the peduncles minutely glandular j 



bracts shorter than the pedicels; stamens mostly 6 ; style 2-cleft; achenium 

 round-ovate, black and shining, with the sides convex. Muddy banks, 

 Florida, and westward. Sept. - (Jet. Stem 3 -4 high. Leaves 6' 

 10' long. Spikes 2' -4' long. Flowers white. 



4. P. Muhlenbergii, Watson. Stem stout, pubescent above; leaves 

 '>'- 6' long, broadly lanceolate, acuminate; spikes erect, racemose or in pairs, 

 linear cylindrical, close-flowered, l'-2' long; flowers large, rose-colored; 

 achenia compressed. Muddy banks, Florida, and northward. 



5. P. Pennsylvanicum, L. Stem smooth below, the branches and 

 peduncles glandular; leaves short-petioled, lanceolate ; spikes erect, oblong, 

 obtuse, close-flowered ; flowers large, rose-color ; stamens mostly 8 ; style 2- 

 cleft ; achenium orbicular, with the sides concave. Wet places. July - Sept. 

 Stem l-3 high. Leaves 2' -4' long. Spikes l'-U' long. 



* * Sheaths fringed with brist.li/ hairs: nchenia 3-angled, or (in N~os. 6 and 8) 

 sometimes lenticular : stamens mostly 8. 



6. P. Persicaria, L. Stem smooth, branching from the base, erect or 

 diffuse; leaves lanceolate or oblong, sheaths short, nearly smooth, fringed 

 with a few short bristles ; spikes short, oblong ; flowers rose-color; stamens 

 6 - 7 ; achenium lenticular or 3-angled, smooth and shining. Waste places. 

 Introduced. July. Stem 1- 11 high. Leaves 2' -4' long, often with 

 a dark triangular spot in the middle. Spikes A'- 1' long. 



7. P. acre, Kunth. Stem slender, smooth, creeping at the base ; leaves 

 lanceolate, and, like the white calyx, dotted with pellucid glands; sheaths 

 smoothish, long-fringed at the throat ; spikes 1 - 3, filiform, loose-flowered ; 

 stamens 8 ; style 3-parted ; achenium 3-angled. (P. punctatum, Ell.) Ditches 

 and margins of ponds, Florida, and northward. July -Sept. ^ Stem 

 1 -3 long. Leaves 2' -4' long, very acrid. Spikes 2'- 3' long. 



8. P. Hydropiper, L. (COMMON SMAETWF.ED.) Annual, smooth; 

 leaves lanceolate, punctate, acrid ; spikes slender, interrupted, nodding 



