702 POYYGONACE<ffi. (BUCKWHEAT FAMILY.) 



1 1 Annuals. Flowers hexandrous. 

 4 P. Hydropiper, 5 Pesicaria, 9 lapathifolium. 



* * * Stems climling. Flowers 3-6, clustered in axils. Stamens 8, 



stigmas nearly sessile. Leaves cordate-sagittate. 



7 P. Convulvulus, 8 dumetorum. 



* * * * Flowers clustered in the axils, or solitary, formhig leafy or leajless 

 spilces. Stamens 8-5, the inner 3 filaments ovate at lase. Ochreoles 



ciix>shaped. 



t Annuals. 

 I Ochrece pellucid, imdivided, at length more or less f ringed-toothed, 



9 P. polycnemoides. 



\ X OchrecB Iroicnish at hase, pellucid, hifid, at length fringed. 



10 P. Bellardi, 11 pulchellum, 13 avieulare. 



1 1 Perennials with more or less herbaceous stems. 

 \ Ochrem hifid, usually many-nerved. 

 13 P. eqiiisetiforme, 14 maritimum, 15 Aleppicum. 

 \ \ Ochrem undivided, hut at length fringed at tip, 2-feic-7ierved. 

 16 P. alpestre, 17 herniarioides. 



1 1 1 Perennials, with shruhhy hase, and rigid branches. 

 \ Ochrem hifid, many-nerved, at length fimbriated. 

 ISP. setosum, 19 luzuloides. 



I I Ochrece undivided, at length fimh'iated. 

 20 P. Libani. 



1. P. Bistorta, L. 1i Bistort. .3 to .8 ; root-stock thick, 

 twisted ; stem simple. Leaves glaucescent-puberulent at under surface, 

 revolute-margined, the lower ovate-oblong, truncate or cordate at base, 

 .1 to .2 long, borne on a long petiole which is winged toward tip, the 

 upper much smaller, lanceolate, clasping at base; ochrese long, brown. 

 Spike dense, oblong, .03 to .05 long, .01 broad; ochreoles ovate, 

 subulate ; perigonium pink ; stamens exserted — June — Alpine Lebanon 

 (Tristram). 



2. P. ainpliibiuiii, L. 1^ Water Persicaria. Root-stock creep- 

 ing. Leaves oblong to oblong-lanceolate, .1 to .15 long. Spikes 

 terminal, long-peduncled, oblong, .015 to .03 long; ochreoles ovate, 

 acute; flowers 5-androus, piuk- Summer — Lebanon. 



Var. aqua ticu 111, Will d. Floating ; ochreee not ciliate ; floating 

 leaves long-petioled. 



Var. terrestre, Willd. Stem erect; ochr ex ciliate ; leaves nearly 

 sessile, lanceolate, narrower and more acute, sometimes appressed- 

 scabrous. 



3. P. serruIaUim, Lag. 2f .5 or more; stems prostrate, rooting 

 below, then ascending, branching. Ochreae appressed - bristly, the 

 margin furnished tcith cilice, often as long as sheath ; leaves nearly sessile, 

 rounded or subcordate at base, linear-lanceolate, appressed-ciliate at 



