POLYGONACEjE. (BUCKWHEAT FAMILY.) 373 



* * Sheaths ciliate or fringed with bristles. 

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



6. P. Careyi, Olney. Stem much branched, upright (3 -5 high), glan- 

 dular-bristly ; leaves lanceolate, bristly on the midrib and margins ; spikes don- 

 gated, cylindrical, drooping, 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. (J) Waste and 

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

 not acrid. (Nat. from Eu.) 



8. P. HYDROP!FER, L. (SMART-WEED.) 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 flattish, or ob- 

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

 (Nat. from Eu.) 



- - Root 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, whitish 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, tapering 

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

 dular-dotted; style half 3-cleft. (P. mite, Pers., not of Sc/irank.) 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 fllaments awl-shaped, 3 of them broader at the base : stigma* 

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

 commonly annuals, smooth and axillary, with small leaves : flowers sometimes crouxl- 

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



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

 and cut-fringed or torn. 



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

 Prostrate or spreading ; leaves sessile, lanceolate or oblong, pale ; flowers apparently 



