702 POYVGONACEJS. (BUCK"\VHEAT FAMILY.) 



1 1 Annuals. Flowers hexandrous. 



4 P. Hydropiper, 5 Pesicaria, 9 lapathifolium. 



* * * Stems cVniibing. Floicers 3-G, clustered in axils. Stamens 8, 

 stigmas nearly sessile. Leaves cm^date-sagittate. 



7 P. Couvulvulus, 8 dumetorum. 

 :): * ■•=.= * Flowers clustered in the axils, or solitary, forming leafy or leajiess 

 qnkes. Stamens 8-5,, tlie inner ^filaments ovate athase. Ochreoles 



cvjy-shaped. 



t Annuals. 

 I Ochrece pellucid, ^individed, at length more or less f ringed-toothed. 



9 P. polycnemoides. 



\ I Ochrece Irownish a^t hase, pellucid, Ujzd, at length fringed. 



10 P. Bellardi, 11 pulchellum, 12 aviculare. 



1 1 Perennials icith more or less herbaceous stems. 

 X Ochrece hifid, usually many-nerved. 

 ]3P. equisetiforme, 14 maritimum, 15 Aleppicum. 

 I \ Ochrece undivided, hit at length fringed at tip, 2-feiD-nerved. 

 16 P. alpestre, 17 herniarioides. 



1 1 1 Perennials, loith shrulhy hase, and rigid hranches. 

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

 18 P. setosum, 19 luzuloides. 



\ \ Ochreoi undivided, at length flonhnated. 

 20 P. Libani. 



1. P. Bistorta, L. 21 Bistort. .3 to .8 ; root-stock thick, 

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

 rcvolute-margined, tlie 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. aiiipliibiuiii, L. 21 Water Persicaria. Root-stock creep- 

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

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

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



Var. aquaticuiiijWilld. Floating; ochrcge not ciliate; floating 

 leaves long-petioled. 



Vav. tcrrestre, Willd. Stem erect; ochr es^ ciliate ; leaves nearly 

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

 scabrous. 



3. P. serrulatum, Lag. 21 .5 or more; stems prostrate, rooting 

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

 margin furnished with cilif£, often as long as sheath ; leaves nearly sessile, 

 rounded or subcordatc at base, linear-lanceolate, app'essed-ciliate at 



