416 POLYGOXACE^E. (BUCKWHEAT FAMILY.) 



pale or whitish ; style 2-clcft, or not parted to the base. We have, sparingly, ran 

 INCAXUM, Koch (P. incamim, Wittd.'), 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. PERSIC\RIA, L. (LADY'S THUMB.) Nearly smooth and glabrous 

 (12' -18' high); sheaths more or less bristly -ciliate ; 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 ; 

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

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

 mon. Flowers greenish-purple. (Nat. fromEu.) 



i- -- 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 : sheailis fringed with bristles : 

 whole herbage pungently acrid! 



8. P. Hydr6piper, 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. &ere, 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. punctatum, 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'-2' long); flowers small, flesh-color 

 or nearly white ; stamens 8 ; style 3-cleft ; nchenium sharply triangular, smooth and 

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

 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 5 ; 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, Moench. P. coccineum, Muhl., &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 



