BUCKWHEAT FAMILY. 371 



^ 4- Sheaths with an abruptly spreading leafy border (which sometimes 

 falls off), or else the sheaths and bracts bristly -ciliate. 



** Style 2-cleft, and akene somewhat flattened ; sepals not punctate. 



= 11 Stem rooting at base, ascending, 



P. Hart-w^rightii, Gray. Stem very leafy, the leaves narrow and 

 short-stalked ; stems rough-hairy, at least on the sheaths and bracts ; 

 sheaths generally with a conspicuous, leafy border ; flowers and fruit 

 like P. araphibium. Wet or muddy places, N. Eng., W. 



= = ® Stems erect. 



P. Cireyi, Olney. Swamps from Penn., N. and E. ; leaves narrowly 

 lanceolate, roughish, tapering both ways ; sheaths margined or ciliate ; 

 peduncles glandular, bristly ; stamens 5. 



P. orientate, Linn. Prince's Feather. Gardens and cultivated grounds, 

 from India ; with large, ovate, pointed leaves, and 7 stamens ; very tall, 

 with ciliate or bordered sheaths, soft-hairy ; flowers in cylindrical nod- 

 ding spikes. 



P. Persicaria, Linn. Lady's Thumb. Nat. from Eu., near dwellings ; 

 about 1° high ; upper face of leaves with a dark blotch near the middle ; 

 sheaths somewhat bristly-ciliate ; spikes oblong, dense, erect, on naked 

 peduncles ; flowers greenisli-purple ; stamens mostly 6 ; style 2-3-cleft ; 

 akene either flattish or triangular. 



*■*■ tf Style generally 3-parted and the akene triangular; sepals mostly 



dotted. 



= Herbage not acrid nor punctate with pellucid dots. 



P. hydropiperoides, Michx, Stems slender, rising out of shallow 

 water, l°-3" high ; leaves narrowly lanceolate or lance-oblong ; sheaths 

 hairy and fringed with long bristles ; spikes erect, slender ; flowers 

 small, pale or white ; stamens 8 ; style 3-cleft ; akene sharply triangular. 

 Common. 2Z 



= = Herbage (smooth) pungently acrid ; leaves and pale sepals marked 

 with pellucid dots or glands, in which the acrid quality resides. 



P. ^cre, HBK. Water Sjmartweed. Stems rooting at the decum- 

 bent base, rising 2°-4- high ; leaves lanceolate or linear, taper- pointed ; 

 spikes slender, erect ; flowers whitish or pale flesh-color ; stamens 8 ; 

 akene sharply triangular, shining. Common in wet places. 2/ 



P. Hydrdpiper, Linn. Common S. or Water Pepper. Low or wet 

 grounds N. ; l'^-2° high; leaves oblong-lanceolate; spikes nodding, 

 mostly short ; flowers greenish-white ; stamens 6 ; akene either flat or 

 obtusely triangular. 



« * Leaves ovate, short-petioled ; sheaths cylindrical, f ringed-hairy ; green- 

 ish flowers IS from each bract of the long and slender spikes, unequally 

 4-parted ; the 2 styles reflexed on the lenticular akene and hooked at the tip. 



P. Virginidnum, Linn. Nearly smooth, 2°-4° high ; leaves rough- 

 ciliate, ;j'-6' long ; flower somewhat curved ; stamens 5. Frequent in 

 thickets. % 



« * ♦ Leaves heart-shaped or arrow-shaped, petioled; sheaths half- 

 cylindrical. 



■»- Tear Thumb. Stems with spreading branches, the angles and petioles 

 armed with sharp reflexed prickles, by which the plant is enabled almost 

 to climb ; flowers in pediuicled heads or short racemes, white or flesh- 

 color. (I) 



P. arii6liuin, Linn. Low grounds ; leaves halberd-shaped, long-peti- 

 oled ; tlie peduncles glandular- bristly ; Btftwens 6 ; styles 2 ; akene len- 

 ticular. 



