POLYGONUM.] POLYQONEJ&. 307 



DIVISION III. APET'ALJl. 



OKDER LX. POLYGONS' JE. 



Herbs rarely shrubby. Leaves alternate, simple, quite entire or serru- 

 late ; margins revolute in bud ; petiole dilated ; stipule sheathing, scarious. 

 Flowers usually 2-sexual, pedicels jointed. Sepals 3-6, petaloid or her- 

 baceous, free or connate, persistent, imbricate in bud. Stamens 5-8, 

 rarely more or less, perigynous or hypogynous, opposite the sepals; 

 anthers 2-celled, bursting outwards or inwards. Disk glandular annular 

 or 0. Ovary free, ovoid, 3-gonous or compressed ; styles 1-3, stigmas 

 capitate or penicillate ; ovule 1, basilar, orthotropo"us. Fruit indehiscent, 

 hard, usually enveloped in the perianth. Seed erect, testa membranous, 

 albumen floury ; embryo straight and axile, or lateral and curved, cotyle- 

 dons various, radicle superior. DISTRIB. Chiefly temp, regions ; genera 

 33 ; species about 500. AFFINITIES. With Amaranthacece and Cheno- 

 podiece. PROPERTIES. Root often astringent or purgative ; some yield 

 oxalic and malic acids ; the leaves or seeds of others are alimentary. 



Sepals 5, subequal. Fruit compressed or 3-gonous, wingless...!. Polygonum. 



Sepals 6, 3 inner much larger. Fruit 3-gonous 2. Rumex. 



Sepals 4, 2 inner larger. Fruit winged 3. Oxyria. 



1. POLYG'ONUM, L. 



Herbs. Leaves alternate ; stipules tubular. Flowers 2-sexual, in panicled 

 racemed or spiked clusters ; bracts ochreate. Sepals 5, 3 outer sometimes 

 enlarging in fruit. Disk usually glandular. Stamens 5-8 ; anthers ver- 

 satile. Ovary compressed or 3-gonous ; styles 2-3, stigmas capitate. 

 Fruit 3-quetrous or compressed. Embryo axile or lateral. DISTRIB. All 

 climates ; species 150. ETYM. iro\vs aoid y6w, from the many nodes. 



SECTION 1. Bistor'ta, Tournef. Rootstock perennial. Stem simple, erect. 



Stipules truncate. Racemes solitary, spike-like; pedicels jointed at the 



top. Stamens 8. Fruit 3-quetrous ; embryo lateral, cotyledons thin flat. 

 1. P. Bistor'ta, L. ; leaves obtuse or cordate at the base, petiole 



winged, raceme dense cylindric. Bistort, Snake-root. 



Woods and wet meadows, from Ross and Skye southwards, but not common, 

 and often introduced ; ascends to 1,000 ft. in Northumberland ; very rare 

 and probably not native in Ireland ; fl. June-Sept. Glabrous, except the 

 leaf -nerves beneath. Rootstock woody, twisted, creeping ; roots tuberous. 

 Stems 1-2 ft., strict, slender. Leaves, radical 3-6 in., oblong-ovate, obtuse, 

 waved, glaucous beneath ; petioles 6-12 in., broadly winged above ; cauline 

 subsessile, broader at the base ; stipules |-3 in. Spike, l-2 in. ; bracts 

 cuspidate. Sepals Jin., pink. Stamens exserted. Fruit brown, shining. 

 DISTRIB. Europe (Arctic), N. Asia, W. Asia to the Himalaya. Root 

 astringent and starchy ; used as food in famine-times, and formerly 

 medicinally. 



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