POLYGONACEJE. ^BUCKWHEAT FAMILY.) 373 



* * Sheatlis ciliate or fringed with bristles. 

 *- Root annual: stamens 6-8 : styles most commonly 2 : achenium mostly flat. 



6. P. Careyi, OIney. Stem much branched, upright (3 -5 high), ylan> 

 lularltristly ; leaves lanceolate, bristly on the midrib and margins; spikes elon 

 gated, cylindrical, drooling, on long bristly-glandular peduncles, rather dense (l'-4 ( 

 long-); stamens 6-8; style 2-parted; fruit lenticular, tumid, very smooth and 

 shining. Shaded swamps, Vermont and Maine to Rhode Island, and doubtless 



westward. Aug., Sept. Leaves 4'- 10' long, roughish. Flowers rose-purple, 

 somewhat tinged with green. 



7. P. PERSICARIA, L. (LADY'S THUMB.) Stem smooth (12'-18' high) ,- 

 leaves lanceolate, pointed, roughish, usually marked with a dark triangular or lunar 

 spot near the middle ; spikes ovoid or oblong, dense, erect, on smooth (or at least not 

 glandular) peduncles (!' long); stamens mostly 6; styles half 2 - 3-cleft ; fruit 

 gibbous-flattened or rarely triangular, smooth and shining, (i) Waste and 

 damp places; veiy common. July, Aug. Flowers greenish-purple. Plant 

 not acrid. (Nat. from Eu.) 



8. P. HYDROPIPER, L. (SMAR'T -\VEED.) Smooth (l-2 high), very 

 acrid; leaves lanceolate, pellucid-dotted ; spikes slender, but short, loosely flowered, 

 greenish, drooping; calyx dotted with pellucid glands; stamens mostly 6 ; styles 

 2-3-parted; fruit minutely striate, dull or little shining, flat or flatfish, or ob- 

 tusely triangular. Moist or wet grounds, mostly in waste places. Aig., Sept. 

 (Nat. from Eu.) 



- - Hoot perennial (or mostly so) : stamens 8 : styles 3 : achenium sharply triangu- 

 lar, smooth and shining. (Stems often decumbent or creeping at the base and rooting 

 from the joints : spikes few or single. ) 



9. P. acre, H. B. K. (WILD SMART-WEED.) Smooth, or nearly so (1 



- 3 high ) ; leaves lanceolate, pellucid-dotted ; spikes very slender, erect, interrupted 

 below, ivhitish or flesh-color ; calyx dotted with pellucid glands; style 3-parted. 

 (P. punctatum, Ell. P. hydropiperoides, Pursh.) Wet places; common, es- 

 pecially southward. 



10. P. hydropiperoides, Michx. (MILD WATER-PEPPER.) Stem 

 smooth (l-3 high), the narrow sheaths hairy, fringed with rather long bris- 

 tles ; leaves roughish or oppressed-pubescent, not acrid, narrowly lanceolate, taperi&g 

 to both ends; spikes rather slender, erect (l'-2^' long), rose-color; calyx not ylan 

 dular-dotted ; style half 3-cleft. (P. mite, Pers., not of Schrank.) Wet places, 

 and in shallow water ; common, especially southward. Aug. 



$ 4. AVICULARIA, Meisn. Calyx more or less petal-like, 5-parted : stamens 8, 

 sometimes 3-6 ; the filaments aid-shaped, 3 of them broader at the base: stigmas 

 o, globose, nearly sessile : achenium 3-sided (cotyledons incumbent : albumen horny) : 

 tommonly annuals, smooth and axillary, with small leaves : flowers sometimes crowd 

 ed in interrupted spikes along the leafless summit of the branches. 



* Flwvers truly axillary, 2-3 together, or rarely solitary : sheaths usually 2 - 3-parted 



and cut-fringed or torn. 



11. P. awiculare, L. (KNOTGRASS. GOOSE-GRASS. DOOR-WEED ) 

 Prostrate or spreading ; leaves sessile, lanceolate or oblong, pale ; flowers appar fitly 



