28? BUCKWHEAT FAMILT. , 



P. tdnue. Eocky dty soU : slender, upright, with thread-like branches, 

 along which the upper flowers form a loose leafy spike ; leaves narrow linear, 

 acute ; akene shining. 



§ 2. Flowers collected in terminal spikes or spike-like racemes, rose-jiurple or flesh- 

 color, or rarely white or greenish. . 



* Leaves small and thread-like or at length none : the sheaths truncate, naked, rigid: 



many-jointed raceme with a single flower under each IracU 



P. articulatum. Sandy shores and barrens : a slender little plant, bushy- \ \ ■ 

 branching, 4' -12' high; flowers rose-colored, nodding; stamens 8; akene \ | , 

 triangular. (T) ,, 



* * Leaves ovate, short-petioled : sheaths cylindrical, fringed-hairy : greenisli^ \ ":, - " 



flowers 1-3 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. Virgini&num. Thickets: 2° -4° high, nearly smooth; leaves rough- v k { [ 

 cUiate, 3' - 6' long ; flower somewhat curved ; stamens 5. ^ \\ V V > 



* » * Leaves lanceolate, oblong, or ovate, chiefly petioled: sheaths cylindrical i 



flowers several from each brad of the spike, 5-parted. ' 



■*- Sheaths mostly with an abruptly spreading foliaceous border (which sometimes 

 falls off) : tall, 3° - 8° high, with dense cylindrical nodding spikes of rose- 

 colored flowers, and flat aJcmes. 



P. orient^e, Princes' Feathek. Gardens and cultivated grounds, rfrom 

 India : with large ovate pointed leaves, and 7 stamens. 



P. C^eyi. Swamps from Pennsylvania N. & E. : with lanceolate leaves, 

 glandular bristly peduncles, and 5 stamens. 



■!-■(- Sheaths truncate, without a harder. 



■w Herbage and flowers not acrid nor punctate with pellucid glands or dots. 



= In moist soil : leaves lanceolate : plants nearly smooth. ® 



P. incaru&tum. Tall, 3° - 6° high ; leaves tapering from near the bass 

 to a narrow point (4' -12' long) ; sheaths smooth and naked ; peduncles rough 

 with scattered sessile glands ; spikes linear, nodding ; flowers flesh-color or pale 

 rose ; the 6 stamens and 2 styles included ; akene flat with concave sides. 



P. PennsylvS.llicum. Stems l°-3° high, the branches above and pe- 

 duncles bristly with stalked glands ; sheaths naked ; spikes oblong, thick and 

 blunt, erect ; flowers rose-purple ; stamens 8, a little protruding ; style 2-cleft ; 

 akene with flat sides. 



P. PerBic^ia, Lady's Thumb. Nat. from Bu. near dwellings, about 

 I ° 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. 



= = 7n water : stems rooting below, y, 



P. amphlbium. Water P. Chiefly N. : stems often simple bearing a 

 single ovate or oblong dense spike or head of pretty large and showy rose-red 

 flowers ; leaves oblong, heart-oblong, lance-ovate or lanceolate, mostly long- 

 petioled, often floating ; sheaths not fringed ; stamens 5 ; style 2-cleft. 



P. hydropiperoides. Commonest S. : stems slender, rising out of 

 shallow water 1 '^ - 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. 



**** Herbage {smooth) pungently acrid: leaves and pale sepals marked with 

 pellucid dots or glands, in which the acrid quality resides : sheaths fringed 

 with bristlet, 



P. AoTO, Water Smartweed. Shallow water or wet soil : stems rooting 

 at the decumbent base, rising 2° - 4° high ; leaves lanceolate or linear, taper- 

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

 akene shaiTply triangular, shining. 2^ 



