Polygonum. 



POLYGONACE.E. 



153 



Annual (in the Southern States apparently perennial, and even suffrutescent as in the plant 

 of the Mediterranean shores). Stem diffuse and widely spreading, hard and woody towards 

 the base. Leaves about three-fourths of an inch long, thick, lanceolate or elliptical. Stipules 

 very thin and scarious. Flowers twice as large as in P. aviculore, pale rose-color or nearly 

 white ; the pedicels often distinctly exserted. Stamens included : filaments dilated at the 

 base ; three of them broader than the others. Stigmas nearly sessile, diverging. Achenium 

 triquetrous, more than twice as large as in the preceding species, chestnut-brown, acuminate. 



Sandy coast of Long Island. August. It is not improbable that the southern plant may 

 be only an annual ; for I have not seen the root, and ours is hard and woody at the base, 

 particularly late in the season. The European P. maritimum is said to be a perennial, but 

 this does not constitute a specific difference where the other characters agree. 



16. Polygonum tenue, Michx. Slender Upright Knotgrass. 



Stem erect, acutely angular, slender, branching ; leaves lanceolate-linear, cuspidate ; ochrea? 

 tubular, lacerate and bristly at the summit ; flowers axillary, somewhat solitary, nearly sessile ; 

 achenium triquetrous, nearly smooth, shining. — Michx. fl. 1 . p. 238 ; Pursh, fl. 1 . p. 270 ; 

 Ell. sk. 1. p. 454 ; Torr. fl. 1. p. 401 ; Bigel. fl. Bost. p. 155 ; Meisn. I. c. p. 91 ; Beck, 

 hot. p. 301 ; Darli7igt.fi. Cest. p. 248 ; Hook. fl. Bor.-Am. 2. p. 132. P. linifolium, Muhl 

 cat. p. 41 ; Bart. fl. Phil. 1. p. 186, and fl. N. Am. 3. t. 95. f. 2. 



Annual. Stem 6-12 inches high, roughish on the angles, more or less branched, often 

 from the base ; the branches upright. Leaves sessile, about an inch long and less than one 

 line wide, rather rigid, serrulate-scabrous on the margin. Ochreaj cut into numerous long 

 setaceous segments. Flowers as large as in P. aviculare, solitary or by pairs, on very short 

 pedicels, greenish white. Stamens 8, short : filaments unequal, five of them subulate, the 

 other three dilated at the base. Stigmas 3, sessile. Achenium nearly black, acute ; the sides 

 ovate, concave. 



Dry rocky hills and sterile fields ; frequent. July — August. 



******* Polygon ell a, Michx. Calyx 5-scpallcd ; the sepals nearly equal, or the two outer ones smaller and usually rejlexed : 

 stamens 8 ; filaments of the three that are opposite the sides of the ovary, dilated at the base, and obtusely l-toolhed 

 on each, side : styles 3, very short, spreading ; stigmas capitate : achenium triquetrous, smooth : embryo in the axis 

 of somewhat horny albumen, very slender, a little curved: cotyledons accumbent. — Flowers perfect or polygamous, 

 in paniculate spikes, one from each bract. 



17. Polygonum articulatum, Linn. Joint-weed. 



Annual ; leaves linear ; ochrea? truncate, naked ; spikes paniculate, filiform ; bracts im- 

 bricated , lower ones mucronate, the upper pointless. — Linn. sp. 1. p. 363 ; Pursh, fl. 1. 

 p. 272 ; Ton: fl. 1. p. 405 ; Bigel. fl. Bost. p. 157 ; Beck, bot. p. 304 ; Hook.fl. Bor.-Am. 

 2. p. 133. 



Root often very tortuous. Stem 6-18 inches high, more or less paniculately branched 

 [Flora — Vol. 2.] 20 



