288 BUCKWHEAT FAMILY. 



P. t^nue. Rocky dry soil : slender, upright, with thread-like tranches, 

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

 acute ; akene shining. 



§ 2. Flowers collected in terminal spikes or spikeMke racemes, rose-purple 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 mth a single Jloiver under each bract. 



P. articulfl.tuill. Sandy shores and barrens : a slender little plant, bushy- 

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

 triangular. ® 



* * Leaves ovate, sJtort-petioled : sheaths cylindrical, fringed-hairy : greenish 

 flowers 1 — 3 flrom each hract of the long and ^lender spikes, vnequally 4- 

 parted ; the 2 styles reflexed an the lenticular akene and hooked at the tip, 



- P. Virgirii&,lium. Thickets: 2°-4° high, nearly smooth ; leaves rough- 

 ciliate, 3' - 6' long ; flower somewhat curved ; stamens 5. y. 



» » » Leaves lanceolate, oblong, or ovate, chiefly , pelioled : sheaths cylindrical: 

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



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

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

 colored flowers, and flat akenes. 



P. orient&lGj Pkinces' rEATHEn. Gardens and cultivated grounds, from 

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



P. Ctoeyi. Swamps from Pennsylvania N. & E. : with lanceolate leaves, 

 glandular bristly peduncles, and 5 stamens. 



■1- -1- Sheaths truncate, without a border. 



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



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



P. incarn^tum. Tall, 3°— 6°high; leaves tapering from near the base 

 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. PennsylvanicurQ. Stems l°-3° high, the branches above and pe- 

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

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

 akene with flat sides. 



P. Persie&,ria, 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 ob'.ong, dense, erect, on naked peduncles ; 

 flowers greenish-purple; stamens mostly 6; style 2-3-cleft; akene either 

 flattish or triangular. - 



:= = /n water : stems rooting below.' y, ' 



P. ampbibium. 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-obiong ; sheaths 

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

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



•w- ■>-» llerbage (smooth) pungenlly acrid : leaves and pale sepak marked with 

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

 with bristles. 



P. here, Watek Smartwekd. 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 sharply triangular, shining, y. 



