288 BUCKWHEAT FAMILY, 



P. t^nue. Eocky dry soil ; 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-iike racemes, rose-purple orjiesh- 

 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 bract. 



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

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

 triangular. ® 



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

 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- 

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



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

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



-I- 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 akenes. 



P. orient^e, Pkinces' Feather. Gardens and cultivated grounds, from 



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



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

 glandular bristly peduncles, and 5 stamens. 



-I — I- Sheaths truncate, mthout a border. 



+* Herbage and flowers not acrid nor punctate with pellucid glands or dots. 



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



P. inearn&,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 a styles included ; akene flat with concave sides. 



P. Pennsylv&nieum. Stems lo-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. Persic^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 oblong, dense, erect, on naked peduncles ; 

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

 flattish or triangular. 



== = In water : stems rooting below, y. 



P. amphibium. 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. hydropiperoldes. 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. 



ft- ** Herbage [smooth) pungently acrid: leaves and pale sepals marked with 

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

 with bristles. 



P. ^ere, W.vter Smaetweed. 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, 



