3S8 POLYGOXACE.E. (BUCKWHEAT FAMILY.) 



7. P. articulata, Meisner. Annual; stem much branched, Blender ; loaves 

 narrowly linear, obtuse, deciduous; sheaths truncate, pointless; racemes numer- 

 ous, erect, slender ; bracts truncate, open, the lowest ones pointed ; flowers bright 

 rose-color; sepals oval or roundish, nearly equal, unchanged in fruit; interior 

 filaments rhombic-ovate at the base. (Polygonum artioulatum, L.) — Dry sandy 

 soil, Georgia, and northward. Aug. — Stem 6'- 12' high. Leaves 4'-8'long. 

 Racemes l'-3' long. 



3. POLYGONUM, L. Knotweed. 



Flowers perfect. Calyx 5- (rarely 4-) parted, corolla-like, the lobes nearly 

 equal, erect and unchanged in fruit. Stamens 3-9: anthers roundish. Styles 

 2-3, distinct or partly united : stigmas entire. Achcnium 3-anglcd or lenticu- 

 lar, enclosed in the persistent calyx. Embryo curved on the outside of the 

 albumen. Radicle slender. — Herbs, with alternate, simple leaves, and sheath- 

 ing stipules. Flowers commonly white or rose-color, variously disposed. 



§ 1. Amblyogonon. Flowers in closely-bracted spikes : stamens 7 : style 2-cli ft : 

 achenium lenticular: cotyledons incumbent: albumen mealy. 



1. P. orientale, L. Hairy; stem tall, branching; leaves ovate, acumi- 

 nate, petioled ; sheaths loose, salvcr-form ; spikes panicled, cylindrical, dense, 

 nodding; bracts ovate; flowers large, bright rose-color. — Around dwellings, 

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

 long. 



§ 2. Pkksicaria. Flowers in closely-bracted spikes : stanmis 4-8: styles 2-3, 

 or 2 — 3-clefl: achenium 3-anylcd or lenticular: cotyledons accumbent : albumen 

 horny : sin aths cylindrical, truncate. 



* Sheaths naked: style 2-cleft or 2-partcd: achenium lenticular. 



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

 peduncles, and calyx sprinkled with glandular dots ; leaves lanceolate, long- 

 acuminate, petioled, rough on the margins and reins ; sheaths slender, appressed ; 

 6pikcs racemed, linear, nodding ; bracts spreading, acute, longer than the pedi- 

 cels; flowers small, flesh-color. Stamens 6, style 2-parted ; achenium ovate, 

 with the sides concave. — Ponds, ditches, &c, South Carolina, and west- 

 ward July-Oct. © — Stem 2° -3° high. Leaves C- 8' long. Spikes 1'- 2' 

 long. 



3. P. densiflorum, Meisner. Stem stout, smooth, tumid at the joints, 

 branching above; leaves lanceolate or oblong-lanceolate, tapering at the sum- 

 mit, hut rather obtuse, rough on the margins and veins ; spikes racemed or 

 somewhat panicled, linear, erect, dense-flowered, the peduncles minutely glan- 

 dular; bracts obliquely truncate, obtuse, shorter than the pedicels; Stamens 



mostly <i ; Btyle 2-cleft; achenium round-ovate, black and Bhining, with tho 

 Bides convex. — Muddj bank-, Florida, and westward. Sept and Oct ® — 



Stem 3°-4° high. Leaves 6'- in' long. Spikes 2'-4' Ion-. Flowers while. 



4. P. Pcnnsylvanicum, L. Stem smooth below, the branches ami pe- 

 dum] ighened with hort glandular hairs j leaves short-pctioled, lanceolate, 



