BUCKWHEAT FAMILY. 371 



*■ -t- Sheaths with an abruptly spreading leafy border (which sometimes 



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



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



= 11 Stem rooting at base, ascending. 

 P. Hartwrightii, 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. amphibium. Wet or muddy places, N. Eng., W. 



= = ® Stems erect. 



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

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

 peduncles glandular, bristly ; stamens 5. 



P. o/v'enfd/e, 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. Persicdria, Linn. Lady's Thome. 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 greenish-purple ; stamens mostly 6 ; style 2-3-cleft ; 

 akene either flattish or triangular. 



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



dotted. 

 = Herbage not acrid nor punctate with pellucid dots. 



P. hydropiperoldes, 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. % 



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

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



P. acre, HBK. Water Smartweed. 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. % 



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. (J) 



* * Leaves ovate, short-petioled ; sheaths cylindrical, fringed-hairy ; green- 

 ish flowers 1-3 from each bract of the long and slender spikes, unequally 

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



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

 ciliate, 3'-6' long ; flower somewhat curved ; stamens 6. Erequent 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 peduncled heads or short racemes, white or flesh- 

 color, (f) 



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

 oled ; the peduncles glandular-bristly j stamens 6 ; styles. 2 ; akene len- 

 ticular. 



