416 POLYGONACE^E. (BUCKWHEAT FAMILY.) 



pale or whitish ; style 2-clefl, or not parted to Vac base. Wc have, sparingly, var. 

 j.ncAnum, Koch (P. incanum, Willd.), and only a depauperate form of it, 

 3' -6' high; leaves lanceolate, obtuse, white-downy beneath; spikes barely 6" 

 long, erect. — Borders of Cayuga Lake, New York ( Chickering and Brewer), of 

 Lake Superior (0. B. Wheeler) and farther northward (Bourgeau). — The true 

 P. nodosum, Pers., which connects this species with the next, has not been 

 detected. (Eu.) 



7. P. PersicAria, L. (Lady's Thumb.) Nearly smooth and glabrous 

 (12'- 18' high); sheaths more or less bristly-ciliate ; leaves lanceolate, pointed, 

 xoughish, 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 ; 

 stamens mostly 6; styles half 2-3-cltft ; achenium gibbous-flattened or some- 

 times triangular, smooth and shining. — Waste and damp places: very com- 

 mon. — Flowers greenish-purple. (Nat. from Eu.) 



•*- +- Annuals or perennials : spikes slender, filiform, loosely -flowered or inter- 

 rupted : flowers greenish or whitish, sometimes purplish-tinged : sepals dotted 

 ■ with conspicuous glands : leaves pellucid-dotted : sheaths fringed with bristles • 

 whole herbage pungently acrid! 



8. P. Hydropiper, L. (Common Smartweed or Water-pepper.) 

 Annual, l°-2° high, smooth; spikes nodding, usually short or interrupted; 

 flowers mostly greenish ; stamens 6 ; style 2 -3-parted ; achenium. dull, minutely 

 striate, either flat or obtusely triangular. — Moist or wet grounds; apparently 

 introduced eastward, but indigenous northward. (Eu.) 



9. P. acre, H. B. K. (Water Smartweed.) Perennial, nearly smooth ; 

 stems rooting at the decumbent base, 2° - 5° high ; leaves larger and longer 

 than in the last, taper-pointed ; spikes erect ; flowers whitish, sometimes flesh- 

 color ; stamens 8 ; style mostly 3-parted, and the achenium sharply triangular, 

 smooth and shining. (P. punetatum, Ell. P. hydropiperoides, Pursh.) — Wet 

 places : common, especially southward. 



•*- •*- •*- Perennials, not acrid, aquatic or amphibious : sepals not glandular-dotted. 



10. P. hydropiperoides, Michx. (Mild Water-Pepper.) Stem 

 smooth (l°-3° high), branching ; the narrow sheaths hairy, fringed with bristles ; 

 leaves narrowly lanceolate ; sometimes oblong ; spikes erect, slender, sometimes 

 filiform, often interrupted at the base (l'-2f long); flowers small, flesh-color 

 or nearly white ; stamens 8 ; style 3-chft ; achenium sharply triangular, smooth and 

 shining. (P. mite, Pers., not of Schrank.) — Wet places, and in shallow water, 1 

 common, especially southward. 



11. P. amphibium, L. (Water Persicaria.) Stems somewhat sim- 

 ple, and usually terminated by a single ovate or oblong and very dense spike 

 (6" thick) of rather large bright rose-red flowers ; sheaths not fringed with bris- 

 tles; stamens?*; style 2-defl; achenium biconvex; leaves varying greatly, from 

 elliptical or cordate-oblong to lance-ovate or lanceolate. — The typical plant is 

 var. aquaticum, Willd. (Var. natans, Mcench. P. coccineum, MvhL, &c), in 

 water, nearly glabrous ; leaves long-petioled, floating, elliptical or oblong, some. 

 times heart-shaped at base; spikes short. — Var. terrestre, Willd., grows 

 in shallow water, or in wet soil, or even " in sandy prairies " in Illinois 



