Flex.mon. 15. POLYGONE^. 33. Bristorta. 267 



cidiuin) naked, or joined to the perigonium ; perisperm 

 farinaceous, rarely nearly wanting; coradum inverse, lateral, 

 rarely central; plvmula inconspicuous; radicle above. — 

 Stem herbaceous, rarely shrubby; leaves alternate, sheath- 

 ing at their base, or with an intrafoliaceous adnate sheath ; 

 younger leaves revolute heweaXh', flowers hermaphrodite, 

 rarely unisexual, spiked or racemose. 



Perigonium ^ or ^-parted, not falling off. 



Floii'srs spiked, terminal Bistorta. S3. 



Flotvers spiked or panicled: spikes many Persicae-ia. S't. 



Flowers axillary Polygonum. S5. 



Floivers corymbose ; thecidium 3-sided Fagopyrum. 2Q. 



Perigonium 4 or 6-sepaled, inner ones persistent^outer reflexed. 



Stigmata 3 ; coradum lateral ; 

 inner sepales tubercular at the base Lapathum. 3*7. 



Stigmata 3 ; coradwn lateral ; 

 inner sepales not tubercular at the base .... Acetosa. 38. 



Stigmata 2 ; corculum central ; 

 in7ier sepales not tubercular at the base Oxyria. 39. 



I. 33. BISTORTA. Snakeweed. 



Perigonium 5-parted, persistent; stamens 8; 3 opposite 

 and 5 interposed ; styles and stigmata 3 ; thecidium 3-an- 

 gularj corculum lateral. — Rhizoma tortuous; stem simple; 

 ocrecB 2-valved, 2-flowered; flowers spiked; spike solitary, 

 terminal. 



1. Bistorta major. Great snakeweed. 



Leaves ovate, w^aved ; radical leaves decurrent into a pe- 

 tiole; spike- dense, obtuse. 



;feistorta major, Rait Syn. 147, 1 ; Ger.em, 399, 1. 



Bistorta major vulga-is, Park. 391. 



Polygonum Bistorta, Lin. S. P 316. 



Polygonum amoennm, Salish. Prod. 258. 



Bistort. Oyster loit, Pasdons, Ch<»shire. Patience dock, Manchester, 



Fields and pastures ; perennial ; May and June. 



Stem 18 in. high; leaves beneath, glaucous, veined; spike 

 erect, many-flowered ; /^ow-frs pedicelled.— Young shoots 

 eaten as a potherb ; root strongly astringent, used also in 

 tanning leather. 



